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Peter J. De Smidt
24-Feb-2012, 12:44
DIYS (Do It Yourself Scanner—pronounced like ‘dice’)--Camera Supports and Positioning Thread

Frank Pertronio started this project by suggesting that someone come up with an affordable and contemporary drum scanner, as there is currently huge gap in price and quality between consumer and professional scanners. Domaz suggested using APS-C sensors and using them to take samples of the film, similar to what Gigapan does with large stitched mosaic images. This lead to talk about making a copy stand scanning system using a dslr, a light source and a movable negative stage. Both horizontal and vertical prototypes have been made, or are in the process of being made.

The original thread (http://www.largeformatphotography.info/forum/showthread.php?84769-Making-a-scanner-with-a-DSLR) has become very long and unwieldy. As a result, I’m creating some new specialized threads for future project development.

The new build threads are:
Camera Supports and Positioning (http://www.largeformatphotography.info/forum/newthread.php?do=newthread&f=7),
Lenses (http://www.largeformatphotography.info/forum/newthread.php?do=newthread&f=7),
Negative Stages (http://www.largeformatphotography.info/forum/newthread.php?do=newthread&f=7),
Light Sources (http://www.largeformatphotography.info/forum/showthread.php?87536-DSLR-Scanner-Light-Sources),
Stitching and Blending of Images (http://www.largeformatphotography.info/forum/newthread.php?do=newthread&f=7),
Cameras and Camera Control Software (http://www.largeformatphotography.info/forum/newthread.php?do=newthread&f=7).
Workflow (http://www.largeformatphotography.info/forum/newthread.php?do=newthread&f=7).


These threads are only for positive contributions to the development in the area in question. The project may not succeed, but we’re going to find that out by trying it. But we are not unkind. As the original thread showed, some people have an overpowering urge to say negative things about the project. I’ve created a thread just for this purpose. Please post your negative comments about the project here (http://www.largeformatphotography.info/forum/newthread.php?do=newthread&f=17).

I would like to thank everyone who makes, or has made, a positive contribution to this project!

I'll be summarizing the posts from the original thread about camera supports and positions here soon.

marfa boomboom tx
8-Mar-2012, 08:55
I'll be summarizing the posts from the original thread about camera supports and positions here soon.[/QUOTE]

sketch I used to build from:
69775

the relationship between film and camera back (as if you didn't know) is the key to success. My experience is not to sweat the "micron" accuracy. Just using eyeball and "focus peaking" beats mosts scanners commonly used. Nope, not Lenny et.al. (who the hell is that guy al, anyway?)

keep the system consistent. I used small spots of Lith pinholes at "stop" points along the travel path of the XY frame.

Accuracy is of two types: one that costs much money, the other that costs much time.

rdenney
8-Mar-2012, 09:18
The reason for precision in the movements of the negative and the position of the camera is two-fold:

1.) to prevent, to the extent possible, geometric distortion (i.e., perspective convergence) that will require a lossy correction during stitching.

2.) to maintain accurate focus at the optimal aperture across the entire length and width of the negative as it is moved. Consider that the optimal aperture might be f/5.6, where there will be very little depth of field. If the film is 1mm closer to the camera at one extreme of its movement, you'll have to refocus each image before stitching. And refocusing almost always changes the magnification slightly, leading to other broad corrections that have to be made during stitching.

It's worth some effort to build the system as accurately as possible. Micron accuracy may be unattainable, but the further we are from fulfilling that requirement, the more we will have to correct during stitching.

Rick "hoping to finish up the negative stage and camera mount this weekend" Denney

Nathan Potter
8-Mar-2012, 10:02
I agree with Rick. A principal reason for accuracy between stage and lens is to avoid the necessity for refocusing as one scans across the film. This will limit the distortions that need to be corrected during stitching. Note the criteria below for depth of focus vs f/no.

f/4 = 56 mils
f/5.6 = 78 mils
f/8 = 112 mils

Micron control isn't really needed but a few mils is far from trivial over 6 inches and formidable over an 8 X 10 sheet.
The stage should have some precision leveling screws, preferably with a pitch that will allow a couple of mils of rise over half a turn. A 40 thread per inch machine screw will give 25 mils per turn, which should be adequate. Maybe check focus with lens wide open then stop down to critical aperture.

Nate Potter, Austin TX

Peter J. De Smidt
9-Mar-2012, 08:11
Changing topics a bit, I've got some P99 1/4" thick acrylic on the way for some negative carriers. The carrier will slide on the glass plate on HDPE feet attached to the P99 acrylic. This acrylic has a fine texture to avoid Newton's rings on the base side of the negative. The negative sits base side down on the acrylic. On top of this will be an ABS hold down sheet with a cut out for the negative. There will be some pins for negative alignment. Since we want to avoid negative movement during the process, there should probably be a little force holding the negative in place. This is especially true for roll negatives, as many people have those in strips of 2 to 6 exposures. Thus, unless we build a big carrier, some of the strip will overhang the carrier, just as it does in most enlargers. (Am I right that people will not want to cut down their strips of negatives?)

One idea is to have two (or so) threaded studs coming up out of the acrylic, such that when a knob is lightly tightened, the acrylic and abs sheets, with the negative in the middle, are pressed together. Another idea is to have a hinged carrier with magnetic closure. A third idea is to tape the negative in place and only use the ABS sheet as a mask.

Wet-mounting would be no problem, but then I'd make the carrier out of glass. I may test this way down the road, as I really don't want to wet-mount unless I have to. I dislike covering my negatives in stuff that needs to be cleaned off.

rdenney
10-Mar-2012, 22:04
Here is my final assembly, for the camera mount and negative stage. Given that the light source will be a standalone device, construction is now complete.

69941

The camera stage, from top to bottom, is the camera, with a Really Right Stuff L-plate, clamped into a Sunwayphoto macro rail, which is clamped into a Wimberley Arca-style clamp, which is bolted to a square tube that adapts it to the top of a Velmex slide with 40-turns/inch adjuster, which is bolted to a generic Sinar lens board, which rides on Incra miter-slot guides made for precision wood-working, and held down with four thumbscrew clamps. The Incra guides are screwed to the surface of the bed, which is 3/4" phenolic resin coated tool-bed plywood, which is bolted down to a 1-1/2" granite sink cutout. I added a self-adhesive tape measure to make it easier to remember general positions for each lens. It is in the correct position in these pictures for the Canon 50/2.5 Compact Macro with Life-Size Converter, which is what is installed on the camera.

The whole mounting is quite stiff, but it has no damping and I can feel it ring at about 20 or 25 Hz when I tap the top of the lens hard. I don't feel any movement when the shutter is fired, but I think I'll need a shutter speed 10 times that ring frequency to detune it. That means a shutter speed of at least 1/250 of a second. I'm going to try a slide projector as the light source, so that should allow quite fast shutter speeds.

69943

I also have a bellows arrangement that can be installed on the Arca clamp and slide, too. The Incra tracks provide the range to focus the 50 that is pictured, and also a 135mm lens on the bellows.

When loosened, there is a small amount of play in the Incra tracks--maybe 30 or 40 thousandths. I can align the edge of the Sinar board to the Incra track before tightening the thumbscrews down, however, and achieve alignment within a few thousandths.

The negative stage is build on two precision angles designed for precision joinery in woodworking. The angles are surface-ground for precision within 0.002 over their length, but these are more accurate than that. The lateral movement runs on two IDO linear way slides (LWL9) that are 14" long, providing enough lateral motion to cover the 5" film width. These are precision ball-bearing slides, and are built around an interference fit and provide no play at all. I spent half an hour aligning the two tracks so that the motion would not bind--the two had to be parallel within a few thousandths over their length. These are 0.002" out of parallel at worst, based on measurement.

The vertical motion is on another pair of the same slides, to which I have attached an Omega D2 4x5 holder. It's glassless, but I'm hoping the vertical arrangement will keep the film flat and prevent the issues of using glass. In this picture, a clear plastic 6" ruler is in place of the negative. I've checked the full range of motion, and there is no change in focus over that range. A film test will be more demanding, of course. But there is no wiggle in this apparatus.

The stage is held in place using clips--accuracy in lateral positioning is not required. The mounting holes in the tracks are 20mm apart--a useful dimension. I will also attach the clear metric ruler for the horizontal movement.

69952

Here's a picture of the base. The bolts holding the plywood to the granite are only tight enough to establish a zero clearance. I want the plywood to be able to expand and contract without trying to warp the granite (not that it would succeed even if it tried). The attachments are at three spots, and I've installed rubber feed under the attachment point, so the whole thing sits on three feet and therefore cannot rock. The feet are not at the corners, which puts the whole structure in maximum bending. They are mid-span, so to speak, so that the stage, at least, is balancd over the feet. I an convinced this will stay flat and level.

69953

Rick "leaving for Anchorage and will have to wait for the next steps" Denney

Peter J. De Smidt
10-Mar-2012, 22:33
It looks good, Rick.

You might get negative movement due to it's being heated up by the strong halogen light, but the only way to know if that'll be a problem will be to try it. Hopefully, it'll be a non-issue.

rdenney
10-Mar-2012, 22:41
It looks good, Rick.

You might get negative movement due to it's being heated up by the strong halogen light, but the only way to know if that'll be a problem will be to try it. Hopefully, it'll be a non-issue.

I considered that, but I don't think so. I can back that projector up pretty far if needed. Most of the heat gets blown out the back. As you say, we'll see.

Rick "who needs to dig that projector out of storage" Denney

peter ramm
11-Mar-2012, 09:05
Rick, the image you posted in the stitching thread shows that you have really made progress - and an effort! Looks like you are having fun.

Sorry to introduce one more complexity but I see fairly major compression of the blacks in that image (hard tell from the jpeg, though). The tonal range is impaired? In that case, you need to implement a masking device that covers everything not being imaged and limits the collection angle of the lens. You may want to also put a diaphragm onto the lens itself, closing down to just outside of the active glass - sort of like a Sinar mask. These things will gain you some linearity. Working in a dark room will also help a bit, as film is actually fairly reflective and when we are looking at 1 part in 1024 (10 bits, absolute minimum for a scanning system) that becomes a factor.

rdenney
11-Mar-2012, 11:13
Peter, as I keep demonstrating, I'm losing track of what even I have said. Do you mean the image of the Japanese maple? That was a stitch from a scan in a Nikon scanner. The blocked-up shadows are on the slide--it was Velvia. The Nikon did better than the Epson, though. I'd be tickled if the DSLR scanner did that well.

Rick "who can't scan what ain't there" Denney

jb7
12-Mar-2012, 08:55
That looks good Rick-
really like the handle for what I presume is the fine focus control-

A couple of things-

Regarding your light source-
I read somewhere (I think I linked to it) that the light source should be daylight, since that is the native color balance setting for a DSLR, and that would give maximum DR.
Since you're using a slide projector, you could easily mount up a full blue gel in a slide, and do a custom white balance-

The other point is regarding film flatness-
If I develop myself, I don't use clips, and the sheet is undistorted.

However, films that have been developed on hangers are often distorted- by the clips, and the heat of the process, for colour films.
I've been having trouble keeping those ones completely flat myself, within the tolerance of the depth of field, which, as you have said yourself, is minute-

Looks like a very nicely engineered setup-

Peter J. De Smidt
20-Mar-2012, 12:15
http://www.microcarve.com/mcMV1.html

Some of John's earlier machines were used for:
http://www.microcarve.com/mcMV1.html ,and
http://www.microcarve.com/mcMV1.html

rdenney
20-Mar-2012, 13:40
http://www.microcarve.com/mcMV1.html

Some of John's earlier machines were used for:
http://www.microcarve.com/mcMV1.html ,and
http://www.microcarve.com/mcMV1.html

Peter, all three of the links are the same.

That's actually a tolerable price. But the tricky bit is that the bed is opaque, requiring the light source to sit on top of it, or requiring one to mount the camera on the bed. I first looked at it and added up what I'd spent--whew! Still cheaper. But this one would be easier to automate than what I did.

Rick "rendered still-stuck on this project by unexpected good weather--requiring extensive yard work:mad:" Denney

Peter J. De Smidt
20-Mar-2012, 15:06
Oops. Sorry about that.
http://gigamacro.com/
http://www.smallworldexplorations.com/micro_gigapan_technology.php

I agree. The hardest part would be the light source. In talking with John, currently there's 4" from the mdf platten to the bottom of the Z-axis, which could be increased a bit by using 1/4" aluminum instead of the mdf. He also would make a 6" (or possibly higher) z stage instead of the standard 4" for a bit extra. Unpainted version in the past have been $75 cheaper than painted, but I don't know if that's still an option. I wonder if the bed couldn't be made out of glass or acrylic, perhaps even with the lead screw off to the side. We might lose a little bit sturdiness, but we aren't pulling an end mill through material, and so I doubt it would be an issue. We could also probably get by with much smaller motors than the cnc people use. On the other hand, the other motors are tried-and-true, and if this scanning thing doesn't work out, or we get done scanning all of our stuff, we'd have a nice cnc unit, which could be really handy.

What appeals to me about this design is that it should be very easy to automate, and it could be put together with very simple tools. To make my prototype, by contrast, one would really need a decent table saw and a drill press. In addition, making linear stages looks quite challenging. In particular, machining down the end of a lead screw (or ball screw) to fit a bearing probably requires a lathe, which I don't have, and I expect few of us possess.

Yes, the weather is nice, and I have projects piling up....

I did get my p99 acrylic for my negative carriers in the mail today.

Peter J. De Smidt
21-Mar-2012, 15:33
How about using two of these rails:
http://www.ebay.com/itm/2pcs-SBR16-350mm-Linear-Bearing-Rails-4pcs-SBR16UU-/150781988319?pt=LH_DefaultDomain_0&hash=item231b4e8ddf

The could be attached to the top of my negative stage, one on each side of the glass plate. A piece of aluminum (or whatever) could be used to connect one of the blocks to a block on the other rail. This would give a bar that could easily be moved from one end of the negative stage to the other. On one side, right above the block, mount a lead screw that goes right above one of the rails to a fixed mounting block just past the end of the rail. Turning the lead screw with a stepper motor would move the cross member along the two rails. That takes care of one axis.

Attach a lead screw on the cross member, running parallel to it. This would give us the other axis of movement.

Lead screws could be something like: http://www.ebay.com/itm/12-3-8-16-ACME-Lead-Screw-w-Delrin-Nut-CNC-Router-/110845791547?pt=LH_DefaultDomain_0&hash=item19ceec8d3b

Thoughts?

rdenney
21-Mar-2012, 17:11
How about using two of these rails:
http://www.ebay.com/itm/2pcs-SBR16-350mm-Linear-Bearing-Rails-4pcs-SBR16UU-/150781988319?pt=LH_DefaultDomain_0&hash=item231b4e8ddf

The IKO LWL9 rails that I used could do that, too, and they are much tinier without being in any way weak. But they aren't any cheaper, so this is probably just as good. You'd want two rails and four followers for each direction. I think it would not be too difficult to fasten a pair of rails on four followers for the crossing direction, though it would need some right-angle stiffening unless you can drill holes more precisely than I can. I need a bit of oversize on the holes to allow for alignment--my drill press seems to wiggle just enough to make real precision a challenge. I need to find the runout in that thing and fix it. But I think you'll need very tight holes and precise drilling to use the platforms on those followers to ensure the right angle.

The rails and sliders I bought only stand 10mm above the deck, but they are so tight that two running in parallel will bind solid if the rails are not parallel to about a thousandth.

The lead screw looks good. I could mount that easily on my rig if I wanted to automate it. But that's waaaay farther down the road than I'm prepared to go at the moment!

Rick "wishing the picture of the delrin nut was a little more clear" Denney

Peter J. De Smidt
21-Mar-2012, 17:57
I get the feeling that the type of system I'm thinking of is overkill for our purposes. After all, my carrier rides on the glass plate, and so the positioning system is only used for x-y motion. I just don't know very much about bearings and so on. There must be something that'd ride on rails made of aluminum angle. The system above would give us accuracy to a few thousandths of an inch, once properly set up, but I don't see the advantages of such a high specification for the workings of our project. The only advantage is that these types of parts are very common in cnc machines, and hence they're readily available.

By the way, I'm going to have a phone conference with some of the giga macro people tomorrow. They've indicated that they're willing to help us out a bit.

Peter J. De Smidt
23-Mar-2012, 08:25
Here's an idea for a fairly simple to build x-y stage. The bearings would ride in tracks routed on the top of the negative stage. (Or one could use flat strips of abs, aluminum...to make tracks.)
http://i955.photobucket.com/albums/ae37/peterdesmidt/Simple_Carriage.jpg

Peter J. De Smidt
23-Mar-2012, 11:52
Instead of the four skate bearings, we could use runners in slots, as one would do for a crosscut sled for a table saw. See product A. at: http://www.leevalley.com/US/wood/page.aspx?p=32045&cat=1,43455,43831&ap=1 .

jb7
23-Mar-2012, 13:11
Peter-

You might not want to hear this, but I think you might be trying to solve a problem that doesn't actually exist-
I might have to agree with your previous suspicion that it might be overkill...

Capturing the tiles is the least time consuming part of the process, and introducing further layers of complexity might only lead to unreliability, something else to go wrong. The level of precision needed to align two sets of bearings, whether wheels or sleds, seems to be a little bit unnecessary, given that a plane surface, sliding on another plane surface, should be sufficient in itself. There isn't an actual load that would necessitate any bearings, and planar materials with a low drag coefficient should (does) function very well without them.

Regarding the xy positioning- well, it's a project, so it would be good if it could be made to work. If you were considering scanning industrial levels of film, then I'd say that it's a goal definitely worth pursuing- to the extent that the negative carrier stage should be made removable, so that you could be loading the next one while the first is being automatically scanned. However, I couldn't justify it myself, since the amount of film I'd want to scan to this resolution is very small.

Even if, like my friend in Newry, my scanner suddenly stopped functioning, and I decided to do all my scanning with a DSLR, I'd still be quicker by manually positioning the film, rather than waiting for the Epson to complete a high res scan, as I found out the other night.

I think the main obstacles to be overcome in this project are

Achieving evenness of illumination,
consistency of focus between frames,
finding a lens that has minimal distortion and curvature,
getting through quite a lot of tedious manual assignment of control points for stitching ( though a more generous overlap would definitely help in this regard)
and finally, getting rid of the dust.

Positioning the frame for capture would be at the bottom of this list, for me, though the system I've come up with is very quick and simple, and as I've mentioned elsewhere, the stitching software is completely capable of detecting any anomalies, and compensating for them.

If large featureless areas are a part of your picture, then dust will inevitably become the feature, and it can be used to help correlate the frames.
Ultimately, I think the precision you're looking for isn't actually necessary-

Peter J. De Smidt
23-Mar-2012, 13:59
Hi Joseph,

These are some good things to think about. Having spent a little time messing with some bearings today at our farm supply store, I'm leaning towards agreeing with you that they're unnecessary for our project.

Regarding the goals:
1) achieving evenness of illumination,
2) consistency of focus,
3) finding a lens with minimal distortion and curvature,
4) simplifying and improving stitching,
5) getting rid of dust.

In my case, the biggest pressing issue is 4). Some of the software available does a good job with structured mosaics captured with something like a gigapan. My hope is that getting the sampled areas to be very regular in position will enable the use of the structured settings of the software to eliminate manually adding control points, which for me is just as tedious as spotting. I certainly might be wrong about that. The gigamacro project seems to work pretty well, though, and a motorized Z-axis would allow focus stacking, if needed.

Regarding minimizing dust, I don't have any idea how to do that other than to use standard cleaning techniques. I have a hepa filter running in my scanner area, and I used forced air and a dslr sensor cleaning brush to clean the film.

rdenney
23-Mar-2012, 21:27
Focus consistency requires a flat negative, and motion in the negative stage that maintains a precise distance from the camera. That precision needs to be good enough so that the camera does not have to be refocused, which will introduce some changes in magnification, especially since the motion error will probably accompany an axial error.

And the film really needs to be at right angle to the lens axis, and parallel to the sensor. Error there will cause geometric distortion, and likely focus variation.

It's not that hard to achieve good precision in these dimensions. But it is really hard to achieve if we don't set out to.

The edges of the sensor should be parallel to the motion--that avoids having to rotate each image or deal with stair steps in the tiles.

It's easier, though, to correct lens distortion and falloff using software, as has been discussed at some length. The better the lens and light source at minimizing these, the less work the software will have to do. But there may always be some software correction required--distortion less than a pixel eliminates the need for blending, and blending probably does more damage than correcting distortion. We've discussed that also, and I'm persuaded.

Planes sliding against each other will trap dust and wear or scratch.

I built a vertical film stage so that I could avoid glass and not worry about sag. It also lets me look through the camera with the apparatus at work-surface height. The camera's mount is also loaded normally rather than being cantilevered.

Aligning the slides I used was not particularly difficult, as it turned out. And it's one less thing to worry about.

Using lead screws may not be precise enough to avoid control points (either manually placed or found by the software), I don't think, at least without using a fine stepper motor. The Velmex slide that Peter and I used for focusing has 40 threads/inch. That's 10.6 microns/degree of rotation. My 5D has sensels just a bit smaller, so that thread and a degree wheel on the handle could provide precise positioning of the film stage. But it would be inconvenient in practice without being motorized--that's a lot of turning. And those slides are expensive, especially in long lengths.

Just some points to consider as a reminder.

Rick "hoping for some testing this weekend" Denney

jb7
24-Mar-2012, 04:19
Good luck with your testing-

You appear to have criticisms of my design, though you continue to neglect to address them directly-

Just quickly-

Do you think there is a problem with cantilevering the camera? The camera isn't subjected to any live loads, and the structure is stiff enough to allow focus to be maintained through a complete scanning cycle, at the very least. In testing, I did use a right angle finder return the viewfinder to vertical, but later found that operating the camera via the computer was better than any other method.

You mention the problem with dust and scratching of the glass-
In my testing, the dust in contact with the transparency is the dust that is the problem,
dust on the bottom of the 6mm thick glass isn't a problem at all-
similarly with any scratching that might be induced by sliding a sheet of glass over a sheet of cartridge paper.
I think you'd need to try very hard to scratch the glass, or maybe sprinkle some filings around-

Regarding control points, the worst of them can be deleted, providing you have better ones. The average control point distance on my scan was 1.69 pixels, less than the resolution of the lens, and undetectable at the scales we're dealing with- 1.69 pixels from an image that's 21,000 pixels high. I'm not sure that it's going to be possible to be pixel perfect in an optical system that requires more than 2 pixels to resolve a pair of lines.

As I said, good luck with the testing-
I have no doubt you'll be able to capture higher resolution in fewer pixels, given the dedicated macro optics you've chosen-

I've prepared some full resolution samples from my tests, will post them later this evening-

Peter J. De Smidt
24-Mar-2012, 07:05
It's not that hard to achieve good precision in these dimensions. But it is really hard to achieve if we don't set out to.


I'm doing my best to do so.


Planes sliding against each other will trap dust and wear or scratch.

My carrier consists of a piece of 6x6" P99 acrylic for the bottom, and a piece of 1/4" thick ABS for the top. Under the acrylic are four feet made of uhmw polyethylene. These feet slide on a thick glass plate. The carrier isn't heavy. I doubt that wear will be a big issue.



I built a vertical film stage so that I could avoid glass and not worry about sag. It also lets me look through the camera with the apparatus at work-surface height. The camera's mount is also loaded normally rather than being cantilevered.


I really don't see the cantilevered situation as being a problem. With my very first test, I set a gitzo tripod over a light box. To the center column, I attached a super clamp. To the super clamp, I attached a 410 head. To the head, I attached a PB-4 bellows. Now that setup was cantilevered. But the results were still very close to my Cezanne, and that was using continuous light. With my current setup, I can stand on the negative stage and the camera support structure, basically anything but on the velmex carriage or camera. I doubt that the very small cantilever situation is a problem, and I doubt it is with Joseph's design.



Using lead screws may not be precise enough to avoid control points (either manually placed or found by the software), I don't think, at least without using a fine stepper motor. The Velmex slide that Peter and I used for focusing has 40 threads/inch.
My Velmex has 20 threads/inch, although a 40 threads/inch screw is available. Regarding control points, the only way to find out would be to try it. I doubt the gigamacro uses manually added control points, and they use lead screws for positioning. Yes, I plan on using a stepper motor with 200 whole steps in a revolution. Microstepping will also be an option.

rdenney
24-Mar-2012, 15:03
Okay, some outcomes:

1.) In the Omega holder, the film has about 0.3mm of curl. I put that in the dammit category. But I need to calculate depth of field before becoming too disappointed, and test further.

2.) The slide projector as a light source is unacceptable. In any position, the camera images the projection bulb, which in no position fills the frame. I can still use it, but diffusion is required. A 45-degree reflector ala what Peter has done makes a good diffuser, and I was able to keep going with just propping up a piece of white paper. A piece of diffusion glass inserted as a slide might solve that problem.

3.) I can't tell yet whether the Canon 50mm macro lens at 1:1 is sharpest at f/5.6, f/8, or f/11. But at least that doesn't seem to vary across the frame--the field seems quite flat.

Yes, I know I hit three threads with this list.

Gotta go play a gig--more testing later.

Rick "whose brain isn't wrapping around the slide projector issue at the moment" Denney

Peter J. De Smidt
28-Mar-2012, 17:10
Something like this:
http://i955.photobucket.com/albums/ae37/peterdesmidt/pie_chart.jpg
is useful to past on the knob of a Velmex slide. Idea borrowed from Charles Krebs.

Nathan Potter
29-Mar-2012, 14:48
Okay, some outcomes:

1.) In the Omega holder, the film has about 0.3mm of curl. I put that in the dammit category. But I need to calculate depth of field before becoming too disappointed, and test further.

2.) The slide projector as a light source is unacceptable. In any position, the camera images the projection bulb, which in no position fills the frame. I can still use it, but diffusion is required. A 45-degree reflector ala what Peter has done makes a good diffuser, and I was able to keep going with just propping up a piece of white paper. A piece of diffusion glass inserted as a slide might solve that problem.

3.) I can't tell yet whether the Canon 50mm macro lens at 1:1 is sharpest at f/5.6, f/8, or f/11. But at least that doesn't seem to vary across the frame--the field seems quite flat.

Rick "whose brain isn't wrapping around the slide projector issue at the moment" Denney

Rick, .3mm (13 mils) is pretty good. Depth of focus, Df = 2CN so at N = f/5.6, Circle of Confusion C at 10um (.010 mm.), you have a Df of 0.11mm (about 4 mils). I assume you would choose a COC roughly about the size of the DSLR pixel dimension in order to make use of the inherent resolution of that DSLR. But it is a bit of a task to keep the focus plane centered around +/- 0.15 mm. Of course the Df scales linearly with N so going to smaller aperture N gains you Df leeway at the cost of lens resolution loss. This will be tricky if we want to approach real drum scanning capability in the 5 to 10 um pixel capture, at 1:1, referenced to the film surface. Any higher magnification exacerbates the Depth of Focus problem. But maybe full frame capture at 1:2 is attractive for most large format film. That would yield a 48 X72 mm frame and increase the pixel capture size by a factor of 2 referenced to the film.

Using the slide projector would be tricky since the dim imaging of the bulb filament can be a problem. This possibly due to the presence of a planar lens surface within the projector optical path, or the reflector focal length falling at a critical location forming an aerial image that can be imaged with the macro lens.

As I think more carefully about this the use of a flash source becomes even more attractive. The high speed eliminates vibration, and the 6000K color temp. is friendly to the DSLR. Peter is on the right track here, unless repeatability of intensity is a problem. Also I think there is a way to focus the flash to a near point using condenser lenses to achieve a collimated uniform source that may be highly beneficial in reducing scattered light and achieve a much better Dmax performance. The Dmax performance would be a key attribute to the DSLR approach so may be realizable.

Nate Potter, Austin TX.

Peter J. De Smidt
29-Mar-2012, 19:30
Here's the fairly current prototype:

http://i955.photobucket.com/albums/ae37/peterdesmidt/side_view_2-1.jpg

Here's a Google Sketchup model of a potential linear positing system:http://dl.dropbox.com/u/3595413/sled2c.skp Please be kind, I just started using cad today. Everything is close to the proper scale.
The motors would be: http://www.probotix.com/index.php?view=product&path=14&product_id=152
The linear rails and bearing blocks would be: http://www.ebay.com/itm/160773515442?_trksid=p5197.c0.m619

jb7
30-Mar-2012, 15:13
Nice model Peter-
one suggestion, you might save some space by positioning the threaded screw element (that sticks out the back) beside one of the linear rails-
it might even be possible to lose one of your linear rails on each assembly too.

Also, a while ago, I bought some of these trapezoidal rods, complete with a matching tap- for another project I haven't started yet-

Anyway, these are in the UK, but it might still be useful- being able to tap your own lead nuts might provide some sort of saving-
check out his other items too, but it might be cheaper for you to source in the US-

http://www.ebay.ie/itm/x3pcs-TR10x2D-Trapezoidal-Spindle-Tap-Delrin-/310192810774?pt=UK_BOI_Metalworking_Milling_Welding_Metalworking_Supplies_ET&hash=item4838eeab16#ht_500wt_1374

Peter J. De Smidt
30-Mar-2012, 15:25
Joseph,

Thank you for the suggestions. I had looked for an inexpensive ACME tap recently, but I wasn't able to find one.

The lead screw positioning and bearing rail suggestions are certainly worth looking into. Once I have some of the rails and blocks, it should be fairly simple to do some experimenting.

Peter J. De Smidt
1-Apr-2012, 08:23
While my Sketchup design used cheap linear rails and bearings, they still weren't all that cheap.

Here's a place that has materials that could be significantly less expensive: http://store.makerslide.com/
See also: http://www.kickstarter.com/projects/93832939/makerslide-open-source-linear-bearing-system.
Also, to avoid lead screws, something along these lines might work: http://store.makerslide.com/index.php?main_page=product_info&cPath=6&products_id=41

For aluminum extrusions, the following place has the best prices that I've found: http://us.misumi-ec.com/
Using these would allow someone to put together a system using very few tools.

jb7
3-Apr-2012, 06:32
I've used an interlocking rack system for positioning, and it works fine.

However, I've drawn an xy stage which could be manually controlled, using handwheels, or automated, using stepper motors, controllers, drivers, and software.

Does anyone have any idea about how much extra the automation gear and software would cost, excluding rails and bearings, for the most cost effective system?

Is it possible to run it from a mac, or would I need to install windows?

Is there a GUI that could be used, or would it involve writing code in some arcane language? Because I have problems enough making myself understood in English...

Is there someone who could take on writing an application which would have a GUI, to make the software plug and play for someone like me, who hasn't a clue? Presumably it would require start points, end points, limiters, offsets, and camera control- and the camera control might involve delays for flash recycling, and multiple exposures per frame, perhaps triggered from the computer, maybe directly attached to the camera- or does that software already exist?

Can you make it so I can perform the whole operation by touching a screen on my iPhone, that says 'Initialize Scan' ?

Peter J. De Smidt
3-Apr-2012, 07:33
Hi,

We're still designing the system. This is a little slow as I started using sketchup only a couple of days ago.
Thus we don't know the cost yet. Another big implication for this is the type of motors and drivers needed. We're _not_ making a cnc machine [made to mill wood or metal], and so we don't need 280oz motors. On the other hand, we're going to get some help with the software, and so we might need to use the electrics that our friendly contributors use.
Another thing is we'd like to avoid using commercial lead screws. They are just too darned expensive, especially when one adds up all of the required ancillaries. I'll be running some tests today to see how regular threaded rod with DIY uhmw poly nuts works.
It's way too early to know about the iPhone thing. Of course it could be done...but not by me.

I"d love to see your x-y plan.

jb7
3-Apr-2012, 07:53
Hi Peter -

Well, it actually is a cnc machine, by definition, as soon as you decide to automate it ...

Threaded rod should be just fine- I'm considering 6mm or 8mm.
I don't have any drawings to show, I won't have until it's built, but it's very simple.
It's often the execution that sets these things apart, not the intent- and now that the testing prototype is out of the way, I'd like to build a good looking machine, whenever I get around to it- which will take over a month, at the very least.

Motors should be very light duty, since loading will be minimal, and If removing the requirement for micro-stepping made the thing cheaper, then I think that should be considered.

It looks like the motion control would be an expensive option on this machine, manual positioning would be less expensive. I think the motors might remain an option on mine for a long time...

Old-N-Feeble
3-Apr-2012, 09:08
There's no way I could afford to buy a setup with automated stepping motors nor do I have the skill or patience to build one even if provided excellent schematics/instructions. I could build one on a bilaterally sliding platform with ruled markings though.

Peter J. De Smidt
3-Apr-2012, 10:01
People can do what they'd like. Automation aside, none of this is very difficult. I'm a very basic handyman. If someone just wants a decently high quality scanner, and they have a good digital camera, a couple of us have had systems that will do that for awhile now. Make one. If someone isn't willing to make something, well, then they can buy a normal commercial scanner. I'm not going to be making kits. What I'd have to charge to put together kits would make the system prohibitively expensive. I may eventually have a DIY article, but anyone reasonably handy could make one from the discussions and examples already given, using the materials that are best for them.

You don't want a collimated light source? Then make a diffusion one. You want a manual slide system? That's easy. You want an automated system? The steps to accomplish that are pretty clear. You could just buy a Microcarve MV3, get an extended z-stage, which John already makes, and buy an LED light source like Peter linked to earlier. Drive the system just as a cnc person would. You want a custom UI program to run everything, and it has to be not only good but free? I'd like a good free car.

I don't need another scanner. I have a good one. I'm doing this because the technical challenges are fun and someone might benefit down-the-road. But all of the griping, especially from people who aren't willing to try something themselves, takes all of the fun out of it.

Old-N-Feeble
3-Apr-2012, 10:30
Peter... I'm following these threads with great interest and am eager to learn as much as my feeble brain can absorb. I hope my post didn't seem negative. I didn't intend that at all. I only meant that my version would necessarily need to be very inexpensive and easy to assemble.

jb7
3-Apr-2012, 10:35
Well, free software is not so uncommon- often developed collaboratively within a community, like this one. It's not uncommon, though free cars are.

I think you might be reading this the wrong way, the comment above mentioned considering an attempt to build one without the automated stage- which in my opinion, is a very sensible solution. Just as I have bits of timber lying around, so others might be tripping over stepper motors, and everyone brings what they can. Some skills may not be shared by everyone, and going back to re-read the beginning of the original thread, it's obvious that the vision that has got this project this far is also not a common currency. I remember the comment about building your own car, which, while not free, would be a start...

There will be no single machine that everyone will build- though there's no reason why a set of drawings can't be made which people could use to order materials and components, and a set of instructions which could be used to aid the assembly. Free, of course. If anyone is going to go to the trouble of doing this, the design, and the results, are going to have to be pretty convincing...

Peter J. De Smidt
6-Apr-2012, 17:27
Here's some screen grabs of the sketchup model for those without sketchup:

http://i955.photobucket.com/albums/ae37/peterdesmidt/scannertopdown.jpg

http://i955.photobucket.com/albums/ae37/peterdesmidt/scannersideview.jpg

ludvig friberg
16-Apr-2012, 09:22
Hi there!

I am reading these DSLR threads with great interest. I already have a pretty good mediumformat nikon negscanner but this tickles my brain. I have built a motion controlled pan/tilt head for film that is very accurate for not too much money and I though I would try and come with some new ideas of my own to this interesting project. I have also built a 35mm slide "scanner" out of an slidesprojector that works pretty well, I tried to tackle the dust problem with a diy digital ICE with a light source alternating between visible light and infrared. Had some mixed results and some (expensive) solutions to making it work better. If infrared is of interest I could list my findings.

If one moves the light together with the filmstrip there would be a more consistent set of tiles that is easier to assemble. Otherwise you get any un-eveness repeated on all the tiles. Particularly visible in something of solid color like a bright sky. One can also take a set of pictures of only the backlight and use it to subtract any small variations. Also simpler to build, no chance of things getting scratched or getting stuck between moving parts. Key here is making the lightsource large, very even and as light and slim as possible so it doesnt put more strain then necessary on the motors and make the contraption as small as possible.

A posible solution to accurate automatic stitching is to take two exposures of each tile one with backlight on on another with a projected lightpattern focused on the film, a laser with a sharp grid would work well. The grid would be used for the algorithm to stitch and then the source images are replaced with the backlit epxosures.

Looking only at the mechanical problem of moving the film in a pattern there is several cheap solutions.

All scanners I have looked into are not driven with leadscrews but with a timing belt and two pulleys. I am not saying leadscrews are bad or anything but not a necessity.

The best is to use linear encoders like scanners do. Then the machine knows where it is for real, but its a lot more complex and expensive to both control and build. Steppers on open circuit is a dirtcheap solution. And one can fine-tune it well, since its always doing the same pattern it is easy to find out backlash and compensate for it.

The cheapest is using two dirt-cheap scanners and cannibalize them for parts. All steppers are more or less the same and all can easily be driven, just throw out all electronics but the motors and use the gearing, pulleys and timing belts. Maybe also the shafts and carrige are useful. Perhaps one normal size scanner and one small travelscanner combined?

Drylin sliders or bearing slides with belts can be pretty cheap. with proper gearing and backlash compensation leadscrews is not necessary, there is backlash on leadscrews too anyway . http://www.igus.eu/wpck/default.aspx?PageNr=2370&CL=DE-en

micro x-y mill table like this one http://www.proxxon.com/eng/html/27100.php cost around $100 and i quite easy to convert to use motors
The y travel is only 46mm on this so maybe a bit small. But there is tons of other like this. Theres always linear stages at ebay, quite often motorized at cheap prices. http://www.ebay.com/itm/XY-X-Y-Motion-Linear-Table-Servo-Automation-Stage-Motorized-Movement-mar50-/390408315995?pt=LH_DefaultDomain_0&hash=item5ae626245b#ht_3641wt_1398 this one is with servos but quite often xy tables with steppers are to be found.

For controlling one can either use something very cheap like a arduino http://www.arduino.cc/ with easydriver stepper. http://www.schmalzhaus.com/EasyDriver/ and just hack some simple code together. Its pretty easy for this.

Something like this moves the motor 4000 steps in one direction then 4000 in the other. This is the whole code needed.

int dirpin = 3;
int steppin = 12;

void setup() {
Serial.begin(9600);

pinMode(dirpin, OUTPUT);
pinMode(steppin, OUTPUT);
}
void loop()
{

int i;

digitalWrite(dirpin, LOW); // Set the direction.
delay(100);

Serial.println(">>");
for (i = 0; i<4000; i++) // Iterate for 4000 microsteps.
{
digitalWrite(steppin, LOW); // This LOW to HIGH change is what creates the
digitalWrite(steppin, HIGH); // "Rising Edge" so the easydriver knows to when to step.
delayMicroseconds(200); // This delay time is close to top speed for this
} // particular motor. Any faster the motor stalls.

digitalWrite(dirpin, HIGH); // Change direction.
delay(100);

Serial.println("<<");
for (i = 0; i<4000; i++) // Iterate for 4000 microsteps
{
digitalWrite(steppin, LOW); // This LOW to HIGH change is what creates the
digitalWrite(steppin, HIGH); // "Rising Edge" so the easydriver knows to when to step.
delayMicroseconds(200); // This delay time is close to top speed for this
} // particular motor. Any faster the motor stalls.

}


to add a function to take a picture only requires 3 lines more of code.

Otherwise something with gui and professional drivers and controllers like geckos and a Kflop and Mach3 but it won't be very easy for a beginner. Perhaps the hardcode with Arduino is actually easier to learn and master, whatever hardware route you take. Look here for more code examples on arduino http://www.schmalzhaus.com/EasyDriver/Examples/EasyDriverExamples.html

Microstepping is nice because it takes a lot of vibrations out but it can screw you a bit on accuracy if you don't use proper gearing and try to get accuracy from the micro stepping.

Thats all I could think of right now.

Best regards

Ludvig

Peter J. De Smidt
16-Apr-2012, 09:57
Hi Ludvig,

Thank you very much for posting!

Regarding infrared, sure, I'd be happy to hear what you've come up with. It wouldn't be much use for BW, but it could be a godsend for color.

Regarding the light situation, you're certainly right. Moving the light source would help minimize any recurring patterns. Our issue so far has been to find
a light source that is flat, light, even, high cri, and reasonably priced. There's been a lot of development the last few years with LEDs, and hopefully
some good options will appear fairly soon. One manufacturer we contacted plans on coming out with a high cri led mat by the end of the year. I do like flash
for it's high cri, brightness, and short duration, but making a moving source with flash might be challenging.

Taking pictures of just the light source to use to minimize any irregularities is certainly an option, but ideally I'd like to avoid it.

Your laser idea to help with stitching is interesting and certainly worth investigating. Hopefully precise and repeatable positioning of the samples will
help with stitching the mosaic with a structured panorama type setting, ala a gigapan. Another option is to increase magnification so that grain and defects
provide enough control points.

Moving on to mechanical motions, I've taken apart some free scanners and printers in the last few days, and you're right, they use belts and pulleys.
In addition, they tend to use one bearing rod, as opposed to two parallel rods, with one side of the carriage sliding on a flat metal surface. While this
method gives up some resistance to going out of alignment, it's a neat way to avoid binding.

Since we don't need to take pictures while anything is moving, we don't really need super smoothness of motion. Hopefully the steppers will be fairly precise using whole steps.

Daniel Moore and I have investigated countless rails, sliders, x-y systems..... Many could be made to work, but the better ones are quite pricey.
The trick is finding something for a reasonable cost that others could easily source. It also matters
whether we are going to go with a moving platen system, which would require very high accuracy in the z-plane, or a system that slides the carrier on a sheet of glass.

We are planing on using an Arduino, mine should be arriving this afternoon, and thank you very much for the code. It's terrific that we have someone
with experience using an Arduino helping out on the project.

Regards,
Peter

ludvig friberg
16-Apr-2012, 10:46
Yes LED is probably the best, but the white ones have pretty poor spectrum for color. At least positive, I have only used this on my cinefilmscanner, where all my stuff is reversal. Perhaps negatives are not so crucial I know a lot of filmscanners use LED like my coolscan. I have designed a small backlight for 35mm using a etched plastic with fresnels and diffusors sourced from a edgelit led backlight from a broken digital pictureframe. I guess you have looked into those. It could be interesting sandwiching 3 of those and use red, green and blue leds on them, and maybe infrared. Then one could dial in a pretty good spectrum i belive.

Look here for more on mixing rgb. http://www.cine2digits.co.uk/ click lighting in the menu.

Microstepping is nice and it actually gives you more torque on the motors in some situations. The vibrations of full step negates a lot of torque. Also it makes it a LOT quiter. 1/8 micro stepping is standard and only gives you benefits. It costs more or less the same to drive the motors like this, and you will have less problems with things, like mechanical accuracy. Also its important to use acceleration and deaccelleration so you dont miss steps and you will get more consistant backlash. The smother motion also put a lot less stress on the rig and things dont jerk out of place.

Mmm I guess for prototyping nothing beats aluminum profiles like 8020. They also have some sliders and stuff.

I didnt really get what you mean with moving platen and z acurracy. Do You mean focus stacking?

For infrared the biggest problem is focus. Most lenses are not corrected into Infrared. As I see it you have two solutions, either a corrected lens(expensive) or a automated control over focus. To solve the problem with a corrected lens is best, when changing the focus there is usually some breathing or something can shift. It is very important that the infrared image matches the normal image 100% Otherwise you get a lot of problems in getting good results. Also on the infrared the backlight must be VERY flat. I used some scripts to batch sequences of images to include the infrared images as a extra channel, I could then use VUEscan and also Silverlight to remove the scratches. I also tried out some inpainting algorithms with good result. http://en.wikipedia.org/wiki/Inpainting The latest Photoshop has some new inpainting stuff, havent tried it yet but its probably very good, and PS is easy to automate.

Ludvig

Peter J. De Smidt
16-Apr-2012, 12:14
For their truewhite series, CRI 92, Cree mixes yellow and red leds. The mixing of various colored LEDs holds a lot of promise. One could even adjust the light source to minimize the orange mask on color negative film. I haven't really looked into the led backlit frames. I gave one to my wife to sit on her desk at work a few years ago, and the color shift over time has been awful.

Thanks for the info on micro-stepping. It's very useful! My Arduino just arrived, and I should be able to do some experiments over the next few days.

For good prices on aluminum extrusions, check out: http://us.misumi-ec.com/ They're quite a bit cheaper than 80/20.
For a neat camera positioning system based on extrusions, check out: http://store.makerslide.com/index.php?main_page=product_info&cPath=6&products_id=41

Regarding Z accuracy, we are going to have very limited depth-of-field. Focus stacking could fix this, but at the cost of a lot of added complexity and shutter firings. So we need to keep the negative flat and parallel to the sensor to a high degree, especially as magnification increases. One way to do that is to slide a sandwhich style negative carrier on a flat surface, such as a piece of glass. This is my current system, and it's what I outlined in the sketchup files. With this system, the x-y system only deals with x-y positioning. The Z location is determined by the glass plate and the negative holder.

With a moving platen version, the negative sits on a piece of, for example, P99 acrylic, and the entire piece of acrylic moves to cover the x-y positioning. This is similar to what happens on the Cezanne scanner, although the platen only moves in the x direction in that case. A moving has the advantage of having a large flat surface on which to place the negative, and one doesn't need to project the light source through a thick piece of glass. The downside is that any up and down (i.e. z axis) variation throughout the x-y movement of the stage could effect sharpness. This is an issue for a lot of the x-y positioning stages we've looked at.

Here's a very rough sketch of a moving platen version:
http://i955.photobucket.com/albums/ae37/peterdesmidt/moving_platen.jpg

For example, lets consider the Proxxon stage you mentioned. It's true that it wouldn't be that hard to motorize, but we'd have to add a light stage on top, along with a negative holder. Without actually trying it, it's difficult to know how much z variation would occur over the stage's entire range of x-y motion.

ludvig friberg
16-Apr-2012, 14:31
Actually if z precision is of big importance a compound table is perfect. Its designed to be as square and parallel as possible over its entire movement. Usually its between 0.02 and 0.05mm on cheap tables. Proxxon is actually a very precise brand with good QC it might be even more precise. My milling table is a lot bigger and its a cheap chinese mill, its around 0.01mm, I just measured it with a very precise dial indicator, thats better than I remembered! As long as the lightfixture and filmholder is machined or built parallel to these tolerances it will not introduce more error, that is the beauty of the long precise parallel dovetails in that design.

Also it is mass produced driving price down, its also very heavy and sturdy by design, minimizing vibration.

How much z movement is acceptable on the fstop/lenses you are aiming for? Are you going to wet mount?

When I have some time I will mount a camera and do some tests. What magnification on a full frame sensor are you aiming at? I have some enlarger lenses and bellows somewhere...

Peter J. De Smidt
16-Apr-2012, 15:16
Ludvig,

That's very good info. Hands on experience is very valuable.

With large format, we have been aiming at 1:1 magnification, or perhaps a bit lower. For roll film, 2:1 or even higher could be useful. When reversed, most enlarging lenses perform very well at 4-5x and pretty good at 1-2x.

Regarding z-movement, that's a good question. The higher performance lenses allow a larger aperture, which means less depth of field. Daniel had a figure in mind which I can't remember, but I'll find it and post it.

I have a Velmex stage to hold my camera. It is terrific, but it'd be nice to have something that people can buy new for a non-exorbitant price. They do some up on Ebay quite regularly, though. Our goal is to come up with a set of plans that people can use to build their own scanner. As a result, I'd like to avoid really hard to find pieces.

I look forward to seeing some of your results.

Regarding wet-mounting, I really want to avoid it. I dislike having to clean film unless it's really necessary, due to a risk of damage, and mounting fluid, even Kami, needs to be cleaned off of the film. Moreover, wet-mounting is most beneficial for film flatness when it is used on a drum, where the tension on the cover sheet presses the film against the drum. That doesn't happen when wet-mounting on a flat surface, which I've done a fair bit of.

jb7
17-Apr-2012, 10:10
Thanks for posting Ludwig-

I too have just taken delivery of an Arduino, but can't do anything with it for a while. Timing belts do seem to be the correct way to drive the platform, so I'll be getting some of those too. I look forward to running my first hamfisted piece of code past you in the near future...

I took a walk over the Brooklyn Bridge to NYC Resistor, a hackerspace, last Thursday evening, and got some encouragement from some of the members there, though not any specific solutions. I did outline the concepts, and there were no objections...

One guy, Trammel, used Large Format in conjunction with a 5D, and has hacked the firmware- he reckons that he could program the camera to drive the stage, and perform the functions of an intervalometer, which sounds like fun...

Peter J. De Smidt
17-Apr-2012, 11:11
I wish I had a hackerspace, or something similar, nearby, but I haven't been able to find one.

I have used freecycle to pick up a bunch of old printers and scanners. They are full of useful things, such as stepper motors, linear bearing rods, belts....

I'm going to solder up my motorshield today.

jb7
17-Apr-2012, 11:18
I wish I had a hackerspace, or something similar, nearby, but I haven't been able to find one.



Brooklyn is hardly the next parish for me...
I've heard there is a hackerspace in Dublin, I must try to find it. Good luck with your soldering-

Peter J. De Smidt
18-Apr-2012, 21:17
How much z movement is acceptable on the fstop/lenses you are aiming for?

.

Our theoretical investigations are pointing to about 300 microns at 1:1 and approximately F8. At 2x things get much, much worse, with a dof of about 9 microns.

ludvig friberg
19-Apr-2012, 03:03
wow... thats pretty crazy!

Just to get this straight you talking about micrometers right? so 300 microns is 0.3mm and 9 microns is 0.009mm. Is that like +- , hyperfocal? I would say that it will be VERY difficult to get that kind of accuracy, I mean the sensor need to parallell to film that tolerance, the lens to the sensor. The lens itself must be very precise. The movement needs to be parallell to that tolerance and the film sheet needs to be flat within a few microns...

I dont know how they do it in the Nikon scanner but I can assure you it is at least +- 0.3mm and thats when its sharp! Sometimes it will be more bends and warps in the film and then things get out of focus, but then we are talking about probably 1 mm uneven.

Would it be better to use a small sensor with tighter pached sensels or am I just confused?

I will make some tests with my mill as a base and a 50mm el nikkor at f8 on bellows I guess I will go for 1:1 or slightly more. Do you have any suggestions on what to use for a test subject? I was thinking of printing something and glue it to a pice of aluminum machined on my mill. That will make it parallell to my test setup at least. Maybe I will just print a raster pattern with some numbers to identify and stitch, could be interesting to see how my new printer places the little drops!

Peter J. De Smidt
19-Apr-2012, 07:43
You're right. That is pretty extreme. I'm basing it off of the figures at: http://www.edmundoptics.com/products/displayproduct.cfm?productid=2482 ,
and http://www.edmundoptics.com/products/displayproduct.cfm?productid=1942. Depth of field numbers are always a bit subjective, as they rely on assumptions about acceptable circles of confusion. I have one of the Mitutoyo 2x objectives, and so I'll be able to test it. It's not like the figures I listed are a cliff and quality drops like a stone if you go outside of it. Rather, you'll start to lose detail in the areas where the height variation increases. As you say, it's very doubtful that most commercial scanners have tolerances that tight.

You can certainly mount a photo (or something) to a very flat piece of aluminum, but I've been mounting film directly to a thick sheet of glass.

marfa boomboom tx
19-Apr-2012, 07:59
Do you have any suggestions on what to use for a test subject? I was thinking of printing something and glue it to a pice of aluminum machined on my mill. That will make it parallell to my test setup at least. Maybe I will just print a raster pattern with some numbers to identify and stitch, could be interesting to see how my new printer places the little drops!

good +

I used lithos for my 2nd round targets... scratched Numbers into the emulsion :) --- It felt gooood ---

Peter J. De Smidt
19-Apr-2012, 13:34
Our theoretical investigations are pointing to about 300 microns at 1:1 and approximately F8. At 2x things get much, much worse, with a dof of about 9 microns.

Sorry, that should've been, "At 2x things get much, much worse, with a dof of about 91 microns."

According to Rik at www.photomacrography.net:

"It turns out that the "depth of focus" numbers listed by Edmund and
Mitutoyo do not rest on any assumption about circles of confusion.
Rather, they are based solely on wavefront error and thus represent
what would be MTF effects as seen by a perfect analog sensor. In
addition, their numbers reflect maximum deviation from perfect focus,
so they give what we might call "single-sided DOF" rather than the
"total DOF" that is given by classical formulas in photography."

Peter J. De Smidt
19-Apr-2012, 15:53
More depth-of-field info, according to The Manual of Close-up Photography by Lester Lefkowitz.
At 1:1 magnification and an f-stop setting on the lens of F4, the depth of field is 0.48mm. At F5.6, it's 0.67mm, and at F8, it's 0.96mm.
All of this assumes a maximum circle of confusion of 0.03mm (0.012 in.). That seems a little loose. Some suggest that for an APS-c camera that a better coc is 0.019mm. Using the stricter coc in the DOF formula gives a DOF of 0.43mm at f5.6 on the lens.

Depth of field (at 1:1) = 4ac
a= aperture
c= circle of confusion

ludvig friberg
19-Apr-2012, 16:35
You guys probably already know this but IŽll put this here anyway.

If you dont have one, get one of these http://littlemachineshop.com/products/product_category.php?category=1319044103

and one of these.
http://littlemachineshop.com/products/product_view.php?ProductID=2880&category=1310310429

You can do a remarkable amount of measuring by using these correctly. Especially if you have a moving table and can mount the indicator to it.

You can find out x, y and z precision of you table. If you measure on the lensmount on the camera house you can perfectly within microns align the sensor/camerabody to the table, etc. Also the longer travel indicator can be mounted as and used to find precise focus and camera z positions. Then you know how much yuo move the camera (or lens if on bellows)All for 50 bucks.

http://www.youtube.com/watch?v=VxCvfLqSUDs&feature=related
do this on x y and z of course.

Maybe use a surfaceplate is good as a base? You can get a bigger one for a bit more. Like 12" square perhaps $100
http://littlemachineshop.com/products/product_view.php?ProductID=3068&category=1438824943

if coupled with a heightgage to mount the dslr on it will get VERY square and precise for not too much money
http://littlemachineshop.com/products/product_view.php?ProductID=3092&category=1310310429

shims can be useful to align perhaps?
http://littlemachineshop.com/products/product_category.php?category=758941860

Anyways the cheap machinist tools offer MUCH higher precision at lower prices. Perhaps a new place to look for ideas for parts?

Peter J. De Smidt
19-Apr-2012, 16:55
Thanks for the links. Some of that would certainly be useful.

I have a dial indicator that I use to setup my woodworking tools, as well as various precision straight edges and squares.

mortensen
26-Apr-2012, 03:20
... this is getting more and more interesting - I really appreciate all the effort you guys put into this!
A good friend of mine is currently building a CNC cutter himself, so thankfully I'll have some programming and stepper motor knowledge around, when these design evolve even further

Peter J. De Smidt
8-May-2012, 12:04
Update:

I've been working on tethering my D200 to my Win 7-64 machine. Using Amazon basic cables did not work. Windows did not see the camera. As a result, and on the advice of some knowledgeable folks, I bought a Monoprice 16ft 2 Port USB 2.0 A Male to A Female Active Extension / Repeater Cable for a little over $8. It works fine. I use Control My Nikon to fire the camera using the "delayed exposure" mode, which raises the mirror about 1 second before firing the shutter. CMN sends the file to a folder that Lightroom 4 monitors for auto import. When imported into LR, the file is inverted, and I can compare captures easily. This isn't quite as good as live view, which my D200 doesn't have, but it works well.

I built an indicator wheel for the knob of my Velmex slide. The 4" diameter wheel has 126 evenly spaced lines along it's perimeter. Since the Velmex lead screw is 20 turns per inch, that means that each tick on my indicator wheel represents a change of 1/2560 of an inch, or 0.000390625 of an inch.

I placed a 4x5" Bergger 200/PMK negative on the glass sheet and masked off the negative. Using a reversed 55 mm nikkor at exactly 1:1 using some extension tubes, I took a series of exposures a tick of my indicator wheel apart. Exposure was provided by an SB-28 flash at 1/64th power fired into my mixing box. The grain of the film was clearly visible at 1:1. Examining the pictures at 2:1, 21 of the frames were indistinguishable for detail. That means that the depth of field for this combo is 0.008 inches.

Old-N-Feeble
8-May-2012, 12:45
Well... I found a decent deal on a very nice used 150mm El Nikkor so I bought it in the hope that it will perform well for this (reversed). Now I need to find a nice DSLR.

Peter J. De Smidt
8-May-2012, 12:57
If you're using continuous light, look for a Canon with EFCS. See: http://krebsmicro.com/Canon_EFSC/index.html

Old-N-Feeble
8-May-2012, 13:04
I think I'll look for a flash option for lighting.

Peter J. De Smidt
8-May-2012, 13:33
I think I'll look for a flash option for lighting.

Then most cameras should be fine.

I have a 150mm El Nikkor too. I'll get around to testing it in this application eventually. It would need quite a bit of extension to get to 1:1, though.

Old-N-Feeble
8-May-2012, 13:42
RE 150mm El Nikkor. I eagerly await seeing your tests. You'll be using the center of a very sharp and well-corrected lens. Hopefully, it'll be perform well enough for this purpose.

jb7
8-May-2012, 14:12
... That means that the depth of field for this combo is 0.008 inches.

How did you guys get to the moon using slide rules and feet and inches...

So, about 0.2mm, sounds about right-
There are a lot of numbers in your post, but I couldn't find a mention of aperture?

I've done some more lens testing, I suppose I should update one of the threads.

Peter J. De Smidt
8-May-2012, 14:37
Joseph, the lens was set to F5.6. I look forward to seeing the results of your testing!

Old-N-Feeble
8-May-2012, 14:43
How did you guys get to the moon using slide rules and feet and inches...

We didn't go to the moon. Don't you ever read the conspiracy theory websites?? :p

Oh... and Kodak designed and manufactured their crappy Ektar lenses using slide rules with "inch" measurements. :D Oh... and Henry Ford only made cars with SAE nuts and bolts. :cool: Oh... and we derived our measurements from da' English. :rolleyes:

ludvig friberg
8-May-2012, 15:03
At what aperture does diffraction kick in on that lens at 1:1 with your setup? It would be nice to have a bit more then 0.2mm. I guess it would double at f11? Thats what math tells me. Interesting to see what the trade off is in a real situation. Loss of some overall resolution due to diffraction but gaining overall sharpness due to increased dof. Unless of course 0.2 mm is within the margins of what your machine can perform. 0.2mm is pretty tight though. Need to really get that neg flat and the movement precise.

Peter J. De Smidt
11-May-2012, 13:26
With my 55mm Nikkor reversed and at 1:1, the best aperture turns out to be F8. Both F5.6 and F11 are a bit softer, with the move from f8 to f11 being a bigger difference. My interpretation is that the lens aberrations are being minimized with the move from f5.6 to F8, whereas diffraction is affecting the results at F11. Since my earlier DOF tests were done at F5.6, this means that with my lens at the better F8, we'll have a bit more DOF to play with. I'll check the dof empirically soon.

One thing to note: When doing these tests you have to check for best focus whenever you change aperture. It wasn't a huge difference, but it did affect the result, although the biggest change was from wide open (f3.5) to f5.6. Other lenses might not have a focus shift.

ludvig friberg
12-May-2012, 17:09
Just found this: http://www.flickr.com/photos/13084997@N03/3145125097/
Interesting idea. I have loads of dead harddrives. Any ideas on other cheap electronic external shutters?

Peter J. De Smidt
12-May-2012, 23:23
There were a number of different LF electric shutters made.

ludvig friberg
13-May-2012, 02:38
Yes that is true, I was thinking of easily obtainable things one could put on a BOM. Old electric shutters are very different from one to the other in terms of voltage and mounting diameter and opening diamater. But of course it would be best using a camerashutter. Maybe just use a repair part shutter of a popular DSLR, that will be in stock for many years to come. Yesterday I was in a hardware store buying paint and flooring stuff and saw a proxxon kt 70 compound table on a shelf. I tried it out a bit and its a very nice unit! If I get around to making a mediumformat scanner(I dont shoot much LF) I will probably use this.

Peter J. De Smidt
13-May-2012, 08:38
The Proxxon does look nice. If only it had more than 1-3/16" y-axis travel, it would be a very viable approach

ludvig friberg
13-May-2012, 12:25
Well there is also the kt150, it has 150mm X 150mm travel and is probably even better. For a 4x5 you dont really need more than 110mm on a fullframe sensor.

Its a bit more expensive but still quite reasonable

http://www.amazon.co.uk/Proxxon-Cross-Table-KT-150/dp/B000S6DU94

You get all sorts of retrofits for steppers to.
http://www.damencnc.com/en/machines/retrofit-kits/180

or diy

http://www.youtube.com/watch?v=7IQz9wOCt7k

Old-N-Feeble
13-May-2012, 12:33
Now I'm getting horny...

ludvig friberg
13-May-2012, 14:17
Read up on the k150, its not as nice as the k70 it seems. The nut and screw is of less precision, ie more backlash. This will not be a problem for us though since we have zero load. Its very easy to compensate for backlash since it is constant, well its constant between the 10 or so movements we make. After time and wear it probably will change a tiny bit, and the programming needs a bit of tuning. At least if zero transformation during stitching is the goal. Its also possible to get a really tight delrin nut. That nut will almost not wear at all and can be made a lot tighter so backlash is almost completely gone. Not sure if that is necessary though. Also the is a zillion compound tables out there best to find one in a shop so one can have a feel.

Peter J. De Smidt
13-May-2012, 16:20
One issue with the milling table idea is that it quickly comes close to the cost of something like the Microcarve MV3, http://www.microcarve.com/mcMV1.htm , which has much bigger area of movement, as well as an automated Z-stage for photo stacking. Moreover, both approaches would require a very thin light source. This doesn't mean that either approach is a bad one, but there are still some challenges.

BetterSense
13-May-2012, 21:22
At 1:1, is there any point to reversing a lens?

I can see at the macro range how reversing would help, but I don't see what difference it makes at 1:1.

Peter J. De Smidt
13-May-2012, 21:31
At 1:1, is there any point to reversing a lens?

I can see at the macro range how reversing would help, but I don't see what difference it makes at 1:1.

It all depends on the lens.

With the F-mount, for instance, the distance from the back of the lens to the sensor is approximately 40mm. In the forward position, Nikon's micro lenses are optimized for greater subject lens distances, and so using the lens reversed, in theory, leads to better performance, where the subject to lens distance is about 40mm. I haven't empirically confirmed this yet with my lens, though.

If you look at something like the 2x Rodagon d, Rodesnstock says that it works best forward at 1:2 and better reversed at 2:1. With my initial test at 1:1, it worked significantly better reversed.

If the lens is perfectly symmetrical, then the orientation shouldn't matter.

ludvig friberg
14-May-2012, 00:51
About the Microcarve, I think that is a great solution to our problem. It quite cheap, has all axes of movement/adjustment and best of all, its all thought out. If one can find a good flat lightsource this type of design would work very well. If we need a deeper lightsource then the milling table is no problem since we can just put the camera higher. Also If one build a gantry style machine lke the Microcarve from scratch one can just have a higher gantry. Since we abbly no x or y load it doesnŽt need to be very strong only vibration free. Also very small motors, drivers and powersources can be used since there is no load Speaking of wich how did the motroshield turn out?

This is a cheap and small opensource project that leaves the bottom open. http://www.shapeoko.com/

Peter J. De Smidt
15-May-2012, 10:03
I spent a lot of time investigating CNC rigs, and the Microcarve is the best combination of features, quality and price that I could find. In addition, John has been very responsive to inquiries.

The pluses of a Microcarve, or similar, for our purposes are:
1) It is inexpensive for the level of quality involved. When you add up the costs of a diy version using linear bearing rods, x-y milling tables... you quickly approach the cost of a Microcarve.
2) It has a fairly large range of motion.
3) It can be dismantled/rebuilt without damaging anything. This also means that it should be easy to modify.
4) A computer controlled Z-axis would make it easy to focus stack. This could help with our limited depth-of-field, especially with curly film.
5) If one gets tired of dslr scanning, you'd still have a very capable cnc machine.

The negatives are:
6) Cost. With motors, drivers, power supplies...the cost will approach $1000, not including a light source. While that's not an unreasonable amount for such a capable positioning system, it's too much money for me to commit to a project that I don't really need. I've already spent over $500 on this project.
7) Limited space for a light source.
8) Z-axis is ideal for CNC, but a finer pitch would be better for a scanner. The main reason is that a finer lead screw will not move with the weight of the camera. With the standard one, you have to use the holding power of the energized stepper motor to keep the camera's z-axis height steady. I'm not sure of there's any vibration when the motor's are energized.

A few more points: the standard Microcarve comes with a 4" z-axis. John can make a 6", or possibly longer axis, if needed. The MDF platen could possibly be made out of a thick acrylic sheet, which could help with that light source issue. The design could be changed so that the x-axis lead screw would be moved to the side of the platen, allowing more space for a light source. Additionally, one could built a stand to raise the microcarve up, and also replace the end panels for the x-axis, such that there's more space between the drive lead screw and the platen. This would also give more space for a light source. Finally, one could make new MDF sides that raise the gantry up higher.

Peter J. De Smidt
15-May-2012, 10:27
This is a cheap and small opensource project that leaves the bottom open. http://www.shapeoko.com/

Thanks for posting this, Ludvig. I hadn't seen it, although Daniel and I have investigated Makerslide a bit. Last time we checked they were sold out. The open bottom would make it much easier to adapt a light source to the plan. The issues I'd like more info on is how precise the Z-axis is, and how vibration resistant the unit is. My guess is that the Microcarve would be better in that regard. Being able to see these machines in person would be really helpful!

ludvig friberg
15-May-2012, 17:01
The issue with vibration is not so big if flash is used I guess? Also if one leave some time for settling after a move there is nothing that would vibrate. I see what you mean about having a really nice precise Z-axis, that would be a huge help even just for normal focusing just add a encoder to drive the stepper on the Z-axis. No need to fiddle with the camera or bellows. Just a Live View on high magnification on a laptop it would be very easy to set focus like that.

Since the travel of Z is typically very small I would suggest that you motorize your velmex, that would make it a lot cheaper.

I will not have time for this project until after summer but I am leaning towards motorizing a milling table. I can use the table with my manual mill to get some cnc capability when needed. I have some steppers and other hardware around and i will probably not motorize the z-axis at all. I got pretty good results with my canon ef 100mm macro at f22. So IŽll start with that also since the focus motor inside that lens is controllable through software it makes things a bit simpler.

Peter J. De Smidt
15-May-2012, 19:43
That sounds like a good plan, Ludvig. Working on scanning is more of a winter activity for me, and I doubt I'll make much progress over the summer. Diffraction will be setting in at a set aperture of F22.

ludvig friberg
15-May-2012, 23:44
Yes I can see that, what I read about it it seems up to F16 is pretty good. http://www.photozone.de/canon-eos/488-canon_100_28_50d?start=1
Thanks for the heads up!

jb7
16-May-2012, 06:23
$1000 Peter? That's too much, my first prototype cost me €16, in addition to the junk I already had lying around.

I don't feel comfortable with some of your strategies. I think it would be reasonable to assume that anyone contemplating a DSLR Scanner might be expected to already own a DSLR, and perhaps some sort of tripod head, or macro rail. Maybe even an iPad, which could be the shallow light source you mentioned earlier, that might be needed to go under a ready-made positioning stage. All of these things are easily removable, and are serving an additional role, and could be seen as a given, for many people.

However, the positioning stage is at the centre of this machine, and trying to justify the purchase of a dedicated device, as something that could be re-purposed elsewhere, just seems like a non-starter to me. Especially those simply wanting to scan film, and not get further involved in CNC, or machining.

Those stages look like precision instruments, though as you mentioned, it would be good to see one, to test it first. They look like they would need some real power to drive them, perhaps requiring some bigger and more expensive motors- bigger than a motor that only has to drive a sheet of glass across a flat surface. They're also distinctly non-diy, if that part of the strategy is an important factor...

And another thing- Focus stacking- again, I think the correct strategy will be to ensure the film is stretched as flat as possible, and not make multiple exposures to process later. Thereby removing the need to drive the z axis, and the need to add more processing to the backend.

I've also moved on to other projects, and don't expect to do much more on this over the summer- though I've still got some lens tests to show. Speaking of which, I think the maximum aperture to set has got to be f/11 or larger, assuming 1:1 reproduction...

Peter J. De Smidt
16-May-2012, 08:16
Regarding aperture, I wouldn't use a smaller one than F8 due to diffraction. Doing so will lead to a significant loss of sharpness, according to my tests. But it's easy enough to run your own tests once you have a system built. As always, your own experience is more valuable than the opinions and results of others.

As has been said ad nauseum, there is a wide range of approaches that would work. Some people will want the cheapest solution. Well, we have three manual designs already, and no doubt there's many more approaches that would work. Some people might be in it more for the DIY aspect. They can build as many of the parts themselves as they'd like. (FYI, John from Microcarve has posted tons of info for people who want to build the machine on their own, including completely from scratch. He'll also sell components, if needed. To do this right, you'll need a mill and a lathe.) Others might just want a very capable scanner that's straightforward to build. Given what Coolscan 9000s go for these days, spending $1000-$1500 on a more capable scanner doesn't seem unrealistic.

Regarding having a cnc machine...I've done a bit of investigating possible positioning systems. I've probably spent over 100 hours doing this. What I've found is that using parts to come up with a system that is high enough quality for our use quickly gets us to near the cost of a Microcarve. And with the parts, you still have a lot of precise alignment and construction to do. John has made over a thousand Microcarves, and he's been continuously improving them. That's a level of refinement that going to be very hard for people to match. In addition, an earlier design of his is being used for a commercial product very similar to what we're trying to do, the Giga Macro. I can only speak for myself, but I'd like a cnc machine. I expect that others interesting in building an automated scanner might share that desire.

I agree about keeping film flat. I've stressed that from day one. And by flat I mean with less than 0.008" variance, but this may not be easily achievable, especially with curly film. Wet-mounting won't necessarily solve this, as anyone with experience wet-mounting on a flatbed will know. With a drum scanner, when you pull the mylar tight, you're also pulling the negative against the curved drum surface. When wet-mounting on a flat sheet of glass, when you pull one side of the mylar, you're not pulling the negative down, at least you're not to the same extent as you would be on the drum scanner. If focus stacking in some situations leads to higher quality scans, then I would want to use it. Some other people might as well. Others will be happy shooting at a smaller aperture, and that's fine by me.

Peter J. De Smidt
22-May-2012, 14:42
An inexpensive way to determine position: http://www.micromark.com/Remote-Digital-Readout-24-Inch-Capacity,9899.html

ludvig friberg
23-May-2012, 02:45
Yes these are quite good, I have a similar solution on my manual milling machine. But they have their readouts on the slider.
http://www.arceurotrade.co.uk/Catalogue/Measurement/Digital-Readouts
Maybe easier with fewer cables?

They are a bit more sensitive to swarf and cutting oil than the expensive ones and they eat batteries much faster than my Mitutoyo caliper, which has lasted 4 years without a change!

ludvig friberg
23-May-2012, 06:42
I have worked out my plans for most of the aspects of this but one part is very unresolved in my mind. The issue of mounting the film. Since I am only interested in 120 film I have looked at some different solutions. The Nikon holder is not very good I think, it doesnt hold the negative very flat. The FH-869G to nikon I havent tried but sandwiching the neg between glass is obviously going to make it very flat. Newton rings might be problem though. The Hasselblad flextight solution seems pretty smart. Ideally I would like to have only one piece of glass and be able to mount a strip with three exposures, then I will manually slide the holder to the next exposure. To me the mounting and dustbusting is the most timconsuming part. The simplest is perhaps taping the neg to a piece of glass but its such a hassle to use tape. I have started drawing on some solutions and any ideas are welcome!

Peter J. De Smidt
23-May-2012, 07:58
Please keep in mind that I'm drinking my morning coffee as I type this.

For really curly film, a glass sandwich carrier would keep the film flat. You could use anti-Newton glass or acrylic for the bottom. Place the film base side down on the AN surface, and then place a sheet of clear water white (.i.e. low iron) optical glass over the top. Hopefully since the emulsion side is usually less glossy than the base side, you won't get any Newton's ring. For the top glass, you could also use anti-reflection coated glass which would minimize any interference patterns. The downside is that glass is expensive and delicate.

Another option is wet-mounting with drum scanner fluid, e.g. Kami, to a glass plate, covering the negative with a Mylar sheet. With some systems this leads to a big jump in quality. Wet-mounting made a big difference when scanning on my first scanner, a Canon flatbed, but it doesn't on my Cezanne. That said, I'd like to avoid it. It's expensive, messy, time consuming, and it can lead to film damage. It's not that hard to do, though, and so it is a viable option. If you do this, you'll need a glass surface quite a bit bigger than the negative, as you're using the surface tension of the fluid to help hold the negative and mylar down.

For film that's not so curly, though, I'm hoping to use an open-topped carrier. The bottom will be 1/4" thick P99 acrylic. This is very similar to what Screen uses for the bed of a Cezanne. This will be on the bottom, just as with the glass sandwich carrier. The top plate will be a piece of 1/4" thick black ABS with a hole cut out in the middle just a little bigger than the image. There'll be a top plate for each sized film I'll scan. To mount the film, lay the abs sheet top down on a light table. Position the frame of film over the opening. Use two small pieces of masking tape to hold the negative in place. Place the top sheet onto the AN sheet. (I'll probably have guide posts to aid alignment, and possibly some type of system to hold the sheets tightly together.)

ludvig friberg
26-May-2012, 17:21
I made a sketch based on aluminum profiles and drylin N 27mm sliders. Its quite cheap maybe around 200 bucks. Here is a small animation and a picture of drylin sliders

74217

If you want to fullscreen go to vimeo an watch it there https://vimeo.com/42903492

https://vimeo.com/42903492

BOM
With norwegiean prices(everything is much more expensive here... in us probably half the price if you shop around)
SLIDE CARRIAGE 27MM 39kr x 6 = 234
igus rail 300mm 85kr x 4 = 340
##belt 650mm 2.5 50kr x 2 = 100
##pulley 88kr x 2 = 176

steppers 140 x 2 = 240
driver, easy driver 129 x 2 = 258
arduino 200

20x20 profile 3meter 150
extra profile stuff fasteners 200
glass 100

=
1998

Peter J. De Smidt
26-May-2012, 19:23
Ludvig, that's a nice looking system. Thanks for sharing it!

ludvig friberg
27-May-2012, 14:01
I looked around on some american vendors and updated the BOM with american prices. Its around $250. Here in norway it costs me around 320 but I already have most of the stuff anyway. I look forward to building this.

SLIDE CARRIAGE 27MM 6 x $5 = 30
igus rail 300mm 4 x $13 = 52
##belt 650mm 2 x $5 = 10
##pulley 2 x $7 = 14

steppers 2 x $15 = 30
driver, easy driver 2 x $15 = 30
arduino $25

20x20 profile 3meter $30
extra profile stuff fasteners $12
glass $10

=
243

mortensen
28-May-2012, 12:50
... gets more and more interesting. Again, your work is greatly appreciated.
I still wonder, though, whether the workflow of this dslr-scanner - with mounting, stitching and spotting - will be faster than that of a drum scanner. I know this hasn't been the primary design criteria, but it is quite significant.

Old-N-Feeble
28-May-2012, 13:02
For me it's not about work flow because I'll be scanning very few images. It's more about attaining maximum quality for minimal cost. Having stated that, I'm fairly sure I'd be better off financially by paying to have drum scans done for me. However, I'm a bit of a control freak so this idea interests me.

Peter J. De Smidt
28-May-2012, 13:28
Speed depends mostly on how many frames you're going to take. For instance, suppose someone is scanning 35mm film with a D800. One frame should be plenty and will be incredibly fast. Even exposure bracketing, if needed, would take only a few seconds. If you want to get super high res, you could always stitch two or three frames. That will add significantly to the time involved, but it will still be only a couple of minutes. For this use, a manual slide system would be ideal. For 35mm, I don't know of a faster way to get high quality.

With larger film, the dslr system will take longer, just as it would with another scanner. As long as you keep the magnification reasonable, say 1:1 or less, it shouldn't take all that long to do a film. Even with my manual slide system, it only took me about 2 minutes, max, to take the 25 frames for a 6x6cm negative. Currently, the stitching takes longer, although that depends a lot on the image. Manually adding control points is the big killer. I'm hoping that the precision of an automated stage will greatly lessen the stitching time, but we don't know about that yet.

ludvig friberg
29-May-2012, 03:44
Like I said before I intend to project a laser pattern on the film and run one full cycle like that first when I start each batch, I will the stitch first using the laser pattern to make a perfect stitch. Then just replace the source image sequence with the real negs, hopefully I can do this with scripting so each set of tiles will lay in different folders and the script just churns through them based on that first laser pattern. I assume this only needs to be done once a day, unless the temperature in the room changes a lot or something bumps the setup out of alignment.

I have done some theoretical tests with computergenerated tiles and it looks neat. What stitching software do you guys prefer? I will most likely look for the one with the best scripting.

Peter J. De Smidt
29-May-2012, 07:42
Microsoft Ice is free, fast, and it supports change of position (as opposed to pivoting around the entrance pupil of the lens) stitches. On the down side, it's not very customizable, and there's no way to add control points. So either it works on an image, or it doesn't. I have the non-pro version of Pt-gui. It's very powerful. Autopano Giga is also quite good. I've not been able to get Hugin to work consistently on my system.

ludvig friberg
8-Jun-2012, 13:22
I was in a large hardwarestore today picking up some supplies for my house and I had a look at the drawer slides they had just for fun. I bought a small ball bearing sliding unit 310mm long. It was very cheap, $8 for a pair. I just tried it out with a dial indicator and it is not bad! Its going +- 0.03 mm or so in Z. I think most of that is due to the non polished/milled surface. That is good enough for a prototype and probably for the final unit too. I think its more fun trying to make this a cheap project.

here is a picture and a video of the device.

74925


https://vimeo.com/43690753

Old-N-Feeble
8-Jun-2012, 13:26
You could buy a dozen drawer slides, cherry pick the most accurate ones and return the others.

Cheap is good.
Simple is good.;)

Peter J. De Smidt
8-Jun-2012, 13:36
That's pretty good, and you could always lap the top surface if needed.

An inexpensive solution is terrific. Not only would it allow more people to make one of these, but it could also be a bench mark to see what gains, if any, are gotten by using a more expensive system.

We've been focusing on 1:1, but for many people that would be overkill with large format. (For years I only enlarged 4x5" to fit on an 8x10" sheet of photo paper with 1" boarders.) Using 1:2 or less would lead to much more depth of field and require less tiles. In addition, most 50-65mm standard macros are optimized for less magnification than 1:1.

Old-N-Feeble
8-Jun-2012, 13:40
For me 1:1 isn't overkill because I want the option of printing quite large if I so choose. BTW, rather than a DSLR what about an outdated low resolution MF back? I'm thinking of buying a 16Mp MF back and using a 2:1 (2x life size on sensor) micro lens.

Peter J. De Smidt
8-Jun-2012, 14:08
I have experience with H20 and H25 Phase backs, and to be honest, I was never thrilled with them. They were clunky, finicky and prone to moire. Certainly there are much newer backs with better performance. The advantages for our purposes would be less required tiles, a significant advantage. The disadvantage would be much more cost, larger and heavier equipment, older technology ... The sensor market has made huge advances very quickly in the dslr and smaller segment. For instance, the D800 has better resolution, dynamic range, color depth...than the older phase backs in spite of having a smaller sensor size.

Ideally, we want the highest performing lens at the desired magnification with a pixel density on the chip that'll allow as much of the performance of the lens to come through as possible. According to some of the knowledgeable macro folks, the best performing lenses at 1:1 tend to be shorter focal length lenses; and the best ones out resolve a 16mp dx sensor.

Now if one has a MF system for other uses, then giving it a try would certainly be interesting, but I wouldn't recommend buying one specifically for this purpose. At those prices, a used drum scanner would probably be a much better investment.

ludvig friberg
9-Jun-2012, 05:45
Also the older digital backs arent that much larger, a h20 is 36.9 x 36.9mm and a 5d is 36 Ś 24 mm the 25s are a bit larger at 48.9 x 36.7 but still I think it is not worth it.

Old-N-Feeble
9-Jun-2012, 06:00
I didn't realize the older MF sensors were so small. I assumed they were all 6x6cm or larger. Silly me for assuming. :)

Peter J. De Smidt
26-Jul-2012, 13:56
Here's a neat robotic camera system: http://www.youtube.com/watch?v=9eED6Uot0Yw

On another note, OpenMoCo has a new board available:
http://www.openmoco.org/nanoMoCo

marfa boomboom tx
27-Jul-2012, 10:18
On another note, OpenMoCo has a new board available:
http://www.openmoco.org/nanoMoCo

positioning hack:
http://www.shumatech.com/support/chinese_scales.htm

ludvig friberg
5-Aug-2012, 17:32
Finally got some time to finish the machining on the second axis on the stage and got all the parts for building the electronics. Here are some pictures of my first run. The two rotary encoders are for positioning the stage starting point. Then with a push of a button it goes through a hardcoded array of positions and fire the camera once on each location. It would of course be possible to have a more fancy interface with a LDC and menus with more possibilities but I will just go for a few buttons that do preconfigured arrays. I will probably have one for preview scanning just moving in x and scanning a filmstrip with one exposure per picture. And one at 1:1 with 6 exposures made for 6x6 and 6x7.

Next is to make the lightsource, finish that negative holder and build a nice box for all that cable mess!

78360783617836278363

ludvig friberg
5-Aug-2012, 17:37
more pics
78364783657836678367

https://vimeo.com/46986255

ludvig friberg
5-Aug-2012, 17:45
Here is the code running in this demo.


#include <AccelStepper.h>
#include <Encoder.h>


// Define a stepper and the pins it will use
AccelStepper stepper1(1, 6, 7);
AccelStepper stepper2(1, 8, 9);

Encoder myEnc1(3, 4);
Encoder myEnc2(0, 2);
const int buttonPin = 10; // the number of the pushbutton pin
const int ledPin = 12; // the number of the LED pin
int ledState = LOW; // the current state of the output pin
int buttonState; // the current reading from the input pin
int lastButtonState = LOW; // the previous reading from the input pin
int i;
long lastDebounceTime = 0; // the last time the output pin was toggled
long debounceDelay = 50; // the debounce time; increase if the output flickers
int pos = 0;

void setup()
{
pinMode(buttonPin, INPUT);
pinMode(ledPin, OUTPUT);
Serial.begin(9600);
Serial.println("TwoKnobs Encoder Test:");
stepper1.setMaxSpeed(5000);
stepper1.setAcceleration(1000);
stepper2.setMaxSpeed(5000);
stepper2.setAcceleration(1000);
}
long oldPosition1 = -999;
long oldPosition2 = -999;

void loop()
{
long newPosition1 = myEnc1.read();
long newPosition2 = myEnc2.read();

long newPosition100 = (newPosition1 * 1);
long newPosition200 = (newPosition2 * 1);

if (newPosition1 != oldPosition1) {
oldPosition1 = newPosition1;
Serial.println(newPosition100);}

if (newPosition2 != oldPosition2) {
oldPosition2 = newPosition2;
Serial.println(newPosition200);}




if (stepper1.distanceToGo() == 0);

{
stepper1.moveTo(newPosition100);
}

{
stepper2.moveTo(newPosition200);
}
stepper1.run();
stepper2.run();

int reading = digitalRead(buttonPin);



// check to see if you just pressed the button
// (i.e. the input went from LOW to HIGH), and you've waited
// long enough since the last press to ignore any noise:

// If the switch changed, due to noise or pressing:
if (reading != lastButtonState) {
// reset the debouncing timer
lastDebounceTime = millis();

// this is all that's new to the code
// toggles the ledState variable each time the button is pressed
if (buttonState == HIGH) {
ledState = !ledState;
Serial.println(ledState);
}
}

if ((millis() - lastDebounceTime) > debounceDelay) {
// whatever the reading is at, it's been there for longer
// than the debounce delay, so take it as the actual current state:
buttonState = reading;
}



// set the LED using the state of the button:
// digitalWrite(ledPin, ledState);
if (ledState == HIGH) {
stepper1.runToNewPosition(newPosition100 + 500);
stepper2.runToNewPosition(newPosition200 + 500);

digitalWrite(ledPin, HIGH); // This LOW to HIGH change is what creates the
delay(3000);
digitalWrite(ledPin, LOW); // "Rising Edge" so the easydriver knows to when to step.
delay(30); // This delay time is close to top speed for this
stepper1.runToNewPosition(newPosition100 - 1000);
stepper2.runToNewPosition(newPosition200 - 1000);

digitalWrite(ledPin, HIGH); // This LOW to HIGH change is what creates the
delay(3000);
digitalWrite(ledPin, LOW); // "Rising Edge" so the easydriver knows to when to step.
delay(30); // This delay time is close to top speed for this
stepper1.runToNewPosition(newPosition100 + 500);
stepper2.runToNewPosition(newPosition200 + 500);
digitalWrite(ledPin, HIGH); // This LOW to HIGH change is what creates the
delay(3000);
digitalWrite(ledPin, LOW); // "Rising Edge" so the easydriver knows to when to step.
delay(30); // This delay time is close to top speed for this

ledState = LOW;
}
// save the reading. Next time through the loop,
// it'll be the lastButtonState:
lastButtonState = reading;

}

Peter J. De Smidt
5-Aug-2012, 18:51
Looks great, Ludvig! Thanks for posting the code.

It looks like you used cabinet drawer slides to allow the xy motion. Is that right?
What motors did you end up going with?

ludvig friberg
5-Aug-2012, 19:12
yes most stuff came from a "home depot" type store. Standard metric square aluminum tubing, cabinet drawer sliders etc. All mechanical stuff like belts, pulleys and bearings come from old broken junk scanners and printers. I did machine most of the stuff perfectly square on my mill, but apart from that you can do this build with a hacksaw and a powerdrill. All electronics are from sparkfun. Motors are https://www.sparkfun.com/products/9238 encoder is this one https://www.sparkfun.com/products/10596? it has a dual function as a button I havent implemented yet. I was thinking of having a coarse and a fine mode so its easier to position the stage startpoint. I can do a complete BOM if you want to. I bought some stuff from B&H for syncing up the camera and some IR filters and servos for the IR stuff. But that will come later, my first test indicates that it is pixel perfect repetative. in X and Y but I will get a better idea when its finished and I start to really use it. It seems to compete resolution wise with my coolscan 8000, even outperform it, it seems. Also the speed is MUCH improved. The cost, not so much, a good dslr is pretty expensive. But its a fun project! I will try and find a bruised one to do a full IR conversion, probably something like a 550D with something broken on it like a broken lcd or something else I dont need.

Peter J. De Smidt
5-Aug-2012, 20:05
That's terrific, Ludvig. You've made great progress. Electronics and programing aren't my strong suit, and so it's a very good thing that you've made such good progress on those fronts.
Is the IR stuff for dust reduction using something like Vuescan?

Daniel Moore
5-Aug-2012, 23:45
This is a very approachable design. Ludvig, thanks very much for sharing it. Do you have a measure of it's runout at this point over the target 6x7cm area?

ludvig friberg
6-Aug-2012, 02:02
I havent finished the negative carrier and the whole top frame needs to be trammed or aligned. But when its perfectly aligned it will hopefully not be more then 0.05 mm.

The math tells me I need to be within 0.02mm at my fstop(7.1) but I take that with a grain of salt. I will find out the real limits when trying it out.

this one slider is out by +-0.03 mm.

https://vimeo.com/43690753

ludvig friberg
6-Aug-2012, 09:40
Yes the IR is for dust and stuff. I will use photoshop to do the removal though, the new algorithms from cs5 and up(like content aware fill) are fantastic. I tested it with a raw scan with a IR extra channel from the Nikon scanner, and photoshop is many, many times better than ICE.

ludvig friberg
6-Aug-2012, 11:09
I did some tests by just laying a piece of glass on top of the stage and running a program with a dial indicator measuring of the glass. Over the distance needed for acquiring a 6x7 neg I only had a very small runout or inaccuracy +- 0.01mm. That is almost too good to be true but thats what the dial indicator tells me! Its not even aligned yet! I have been VERY pedantic while machining all the parts though, just didn't think it would pay off that well!

Daniel Moore
6-Aug-2012, 12:25
To clarify, when you say "I did machine most of the stuff perfectly square on my mill" are you referring to all surfaces, ensuring flatness and plane parallelity or simply the ends of the stock where joined? I suspect I already know the answer but best to hear it from you. What you've achieved with these slides is nothing short of amazing.

ludvig friberg
6-Aug-2012, 12:51
I only machined the parts touching each other and I have not machined the surfaces of the slides themselves. There i a weakness to my design though that could be easily fixed by mounting the slides like they are designed to be mounted, rotated 90 degrees but that makes it a bit more complicated to build and it also makes the contraption taller. There is quite a lot of play in z axis the slides in the direction I mounted them but that doesnt seem to matter for this application where there is zero load in z axis. For a machining rig this setup would be a disaster!

Peter J. De Smidt
6-Aug-2012, 14:12
Yes the IR is for dust and stuff. I will use photoshop to do the removal though, the new algorithms from cs5 and up(like content aware fill) are fantastic. I tested it with a raw scan with a IR extra channel from the Nikon scanner, and photoshop is many, many times better than ICE.

That's great news!

Laron
7-Aug-2012, 09:22
wonderful! cant wait to see more of the evolution, thanks for sharing!

Daniel Moore
18-Dec-2012, 13:36
Just discovered Modkit a graphical code editor (http://www.kickstarter.com/projects/modkit/modkit-micro-the-easiest-way-to-program-microcontr). Could be useful. Here's their webpage (http://www.modk.it/alpha). 50.00 to 'join', still in beta it seems. I think it could be just as helpful in learning to code by connecting modules and seeing how they are written out. They don't seem to have setup the free online version yet. I did find a desktop widget but launching it asks again to join for 50.00. I went ahead and did that and will give my impressions in a couple days.

marfa boomboom tx
19-Dec-2012, 11:55
Just discovered Modkit a graphical code editor (http://www.kickstarter.com/projects/modkit/modkit-micro-the-easiest-way-to-program-microcontr). Could be useful. Here's their webpage (http://www.modk.it/alpha). 50.00 to 'join', still in beta it seems. I think it could be just as helpful in learning to code by connecting modules and seeing how they are written out. They don't seem to have setup the free online version yet. I did find a desktop widget but launching it asks again to join for 50.00. I went ahead and did that and will give my impressions in a couple days.

Dan &others:

see: http://arduino.cc/blog/2010/10/05/visual-programming-arduino-modkit-and-the-others/

for a list of 'other' visual program tools.

for modkit in safari, this link http://www.modk.it/editor/preview/
is active.

hth

Daniel Moore
20-Dec-2012, 00:32
Having spent a couple whole days working with Modkit, Amici (won't run on Win 7 x64), Ardublock in Eclipse, I'm ready to say there's no advantage. The reason is that without a knowledge of control systems, functions, and general electronics you are left with a pretty looking GUI and nowhere to go. It's perfect for kids who are being told what to do, put this here, place that there, and Voila! But to get things done we need more knowledge. There's no getting around it. My secret hope was that one of these programs would allow to import an existing project and parse it out into visual blocks. None could, yet. Modkit did have the best experience, but I wouldn't shell out for it yet. There's the free Ardublock, (http://blog.ardublock.com/engetting-started-ardublockzhardublock/)which is much the same as the others if you're interested. To install it, you need to create the folder structure yourself. That means find the sketchbook location if not the default and make the folder there called "tools', and within it make another called "ArduBlockTool", and one more within that called "tool" and finally paste the downloaded "ardublock-all.jar" file within that.

Peter J. De Smidt
8-Jan-2013, 10:32
Here's a test sketch to use with an Arduino and the Adafruit Motor Shield.

I am not a programmer! If I made mistakes, or if there's a better way to do it, please let me know. My steppers should be arriving later this week.

//DSLR XY Test Software V1
//
// X-motor hooked up to Adafruit Motor Shield M1+2
// Y-motor hooked up to M3+4
// Instead of taking an exposure, the program will
// print a message to the IDE Serial Monitor
//
// Image capture will go in the following order:
// 9|8|7
// 4|5|6
// 3|2|1

#include <AFMotor.h> //Load Adafruit Motor Library

AF-Stepper1(200,1) //X-axis stepper
AF-Stepper2(200,2) //Y-axis stepper

Void Setup()

{
Serial.begin(9600); //start serial communication
Serial.print("9 frame positioning test.");

Stepper1.setspeed(20); //A guess
Stepper2.setspeed(20); //Ditto

//if carrier isn't home, then move it home.

Stepper1.step(400,forward,single); //Move carrier left such that
//it's one frame to the right
//of the initial capture area.
//This is another guess.

Stepper2.step(400,forward,single); //Move carrier to the starting
//capture row.

int framenumber=0; //Frame Number Counter
}

Void loop()

{
framenumber=framenumber+1;

switch(frameNumber)
{
case 1:framenumber==1||2||3||8||9

stepper1.step(50,forward,single); //move carrier to next capture area
Stepper1.release(); //de-energize stepper 1 to minimize vibration
Stepper2.release(); //de-energize stepper 2 to minimize vibration
delay(1000); //pause 1 second.
Serial.println(framenumber); //sends the framenumber to the Serial Monitor
//Eventually this'll fire the camera shutter.
break;

case 2:framenumber==4||7

stepper2.step(80,forward,single) //move carrier up to the next row
stepper2.release;
delay(1000);
serial.println(framenumber;
break;

case 3:framenumber==5||6

stepper1.step(50,backward,single);
stepper1.release();
delay(1000);
serial.println(framenumber);
break;

case 4:framenumber==10

stepper1.step(500,backward,single); //start moving carrier home
stepper2.step(560,backward,single);
serial.print("Done!");

}

ludvig friberg
8-Jan-2013, 16:26
cool! Nice to see some code Peter!

I think its best to just jump in like you do and try stuff out. Probably you will find more stuff out when you have the motors driving your rig. A couple of things I would try if I were you is the accelstepper library also from ladyada http://www.ladyada.net/make/mshield/download.html If you have some easing in and out it will help with precision, things wont get jerked out of alignment so easily. You can also move faster between your frames. Another thing is to try and avoid using delay(). The reason is that the arduino is deaf and blind during the delay so if you press a button during a delay it just ignores it. Try and use IsTime() or some other solution instead.

http://www.uchobby.com/index.php/2012/01/21/replacing-delay-in-arduino-sketches-istime-to-the-rescue/

Looking forward to see your rig in motion!

Peter J. De Smidt
8-Jan-2013, 16:33
Thank you for the tips, Ludvig! I'm a complete beginner at this.

Daniel Moore
8-Jan-2013, 17:35
There's a thread on Flickr for a macro photography rig (http://www.flickr.com/photos/reallysmall/8270022807/in/photostream/) with a lot of good information. The code Richard (Really Small) is developing may have a lot of potential for this project.

Peter J. De Smidt
8-Jan-2013, 19:11
//DSLR XY Test Software V1
//
// X-motor hooked up to Adafruit Motor Shield M1+2
// Y-motor hooked up to M3+4
// Instead of taking an exposure, the program will
// print a message to the IDE Serial Monitor
//
// Image capture will go in the following order:
// 9|8|7
// 4|5|6
// 3|2|1

#include <AFMotor.h> //Load Adafruit Motor Library

AF_Stepper Stepper1(48,1); //X-axis stepper
AF_Stepper Stepper2(200,2); //Y-axis stepper

int framenumber=0; //Frame Number Counter

void setup()

{
Serial.begin(9600); //start serial communication
Serial.print("9 frame positioning test.");

Stepper1.setSpeed(40); //A guess
Stepper2.setSpeed(40); //Ditto

//if carrier isn't home, then move it home.

Stepper1.step(400,FORWARD,SINGLE); //Move carrier left such that
//it's one frame to the right
//of the initial capture area.
//This is another guess.

Stepper2.step(400,FORWARD,SINGLE); //Move carrier to the starting
//capture row.


}

void loop()

{
framenumber=framenumber+1;

switch(framenumber)
{
case 1:framenumber==1;

Stepper1.step(50,FORWARD,SINGLE); //move carrier to next capture area
Stepper1.release(); //de-energize stepper 1 to minimize vibration
Stepper2.release(); //de-energize stepper 2 to minimize vibration
delay(1000); //pause 1 second.
Serial.println(framenumber); //sends the framenumber to the Serial Monitor
//Eventually this'll fire the camera shutter.
break;

case 2:framenumber==2;

Stepper1.step(50,FORWARD,SINGLE); //move carrier to next capture area
Stepper1.release(); //de-energize stepper 1 to minimize vibration
Stepper2.release(); //de-energize stepper 2 to minimize vibration
delay(1000); //pause 1 second.
Serial.println(framenumber); //sends the framenumber to the Serial Monitor
//Eventually this'll fire the camera shutter.
break;

case 3:framenumber==3;

Stepper1.step(50,FORWARD,SINGLE); //move carrier to next capture area
Stepper1.release(); //de-energize stepper 1 to minimize vibration
Stepper2.release(); //de-energize stepper 2 to minimize vibration
delay(1000); //pause 1 second.
Serial.println(framenumber); //sends the framenumber to the Serial Monitor
//Eventually this'll fire the camera shutter.
break;

case 4:framenumber==4;

Stepper2.step(80,FORWARD,SINGLE); //move carrier up to the next row
Stepper2.release();
delay(1000);
Serial.println(framenumber);
break;

case 5:framenumber==5;

Stepper1.step(50,BACKWARD,SINGLE);
Stepper1.release();
delay(1000);
Serial.println(framenumber);
break;

case 6:framenumber==6;

Stepper1.step(50,BACKWARD,SINGLE);
Stepper1.release();
delay(1000);
Serial.println(framenumber);
break;

case 7:framenumber==7;

Stepper2.step(80,FORWARD,SINGLE); //move carrier up to the next row
Stepper2.release();
delay(1000);
Serial.println(framenumber);
break;

case 8:framenumber==8;

Stepper1.step(50,FORWARD,SINGLE); //move carrier to next capture area
Stepper1.release(); //de-energize stepper 1 to minimize vibration
Stepper2.release(); //de-energize stepper 2 to minimize vibration
delay(1000); //pause 1 second.
Serial.println(framenumber); //sends the framenumber to the Serial Monitor
//Eventually this'll fire the camera shutter.
break;

case 9:framenumber==9;

Stepper1.step(50,FORWARD,SINGLE); //move carrier to next capture area
Stepper1.release(); //de-energize stepper 1 to minimize vibration
Stepper2.release(); //de-energize stepper 2 to minimize vibration
delay(1000); //pause 1 second.
Serial.println(framenumber); //sends the framenumber to the Serial Monitor
//Eventually this'll fire the camera shutter.
break;

case 10:framenumber==10;

Stepper1.step(500,BACKWARD,SINGLE); //start moving carrier home
Stepper2.step(560,BACKWARD,SINGLE);
Serial.print("Done!");

}
}

Peter J. De Smidt
16-Jan-2013, 20:13
We've been making some progress on the programing front, but we're not ready for prime time just yet. That said, we have a name for our scanner control system: Scanduino.

jb7
17-Jan-2013, 06:49
Good luck with that, and Daniel too-
Will be following with interest, and look forward to pilfering some code someday-

Peter J. De Smidt
2-Mar-2013, 11:21
Here's a video of a very early stages prototype xy-stage: https://www.youtube.com/watch?v=MZ_OrwB90CM

Nathan Potter
2-Mar-2013, 13:12
Peter, quite nice. I didn't notice any backlash in translation although I suppose that would not be too critical for the application here. Interesting that you chose two different rails for X and Y motion but I assume they are driven by the same type of stepper. The real trick is to keep the assembly in the exact plane of focus during translation.

I take it that this is a prelude to a full blown prototype that will scan LF at potentially high rez by stepping then tiling the copies using software.

Nate Potter, Austin TX.

Peter J. De Smidt
2-Mar-2013, 14:09
Hi Nate,

Yes, this is just a prototype to work out control issues.

Btw., the rails are all 450mm fully-supported SBR 16 linear bearing rods. The steppers are 12-volt Nema 17 200 step/rotation models from Adafruit. See: http://www.adafruit.com/products/324. If I were to buy new ones, I'd get slightly bigger ones.

ludvig friberg
4-Mar-2013, 14:56
Sweet rig!
Is it Misumi or similar or did you machine the parts yourself? Can you give me a ballpark figure on the mechanics?

Looking forward too seeing more, keep up the good work!

Peter J. De Smidt
4-Mar-2013, 17:35
Thanks Ludvig. The rails and blocks were from Ebay. The total was $140 shipped for 4-450mm rails and 8 blocks. I'm happy with the quality.

ludvig friberg
29-May-2013, 16:50
Any news here? I am probably going back into this project again later this year. My wife just got bit by the largeformat bug. I have some new ideas too...

Ludvig

Peter J. De Smidt
29-May-2013, 16:58
Hi Ludvig,

Both Daniel and I are currently finishing up our light sources. They both use RGB LED ribbons, and the R, G, and B intensities are controllable separately. Daniel's a little farther along than I am.

The Arduino control program is finished and is working well.

Hopefully, we'll both have fully working devices soon, and when we do, we'll post particulars.

Randy Moe
29-May-2013, 17:08
Verry interesting!



Hi Ludvig,

Both Daniel and I are currently finishing up our light sources. They both use RGB LED ribbons, and the R, G, and B intensities are controllable separately. Daniel's a little farther along than I am.

The Arduino control program is finished and is working well.

Hopefully, we'll both have fully working devices soon, and when we do, we'll post particulars.

ludvig friberg
30-May-2013, 04:27
Interesting!
I was also thinking of using rgb ribbons in a woven grid with diffusion. Also looked into using an acrylic with etched backface and filters like on a led tv, just replacing the ledstrips with very powerful rgbleds. I would guess that the filters from a broken led tv still is a good idea to use to break up a backlit solution. For my 8mm and 16mm scanners I use a sphere as a mixingchamber. Through an opening slightly larger then the FOV on one side I shoot the inside of the sphere where all colors mix perfectly. The hole should not be larger then 5% ideally so in this senario with a large sensor the sphere needs to have a diameter of 7-10 cm. The best part of using a sphere is that its easier to add more leds as you go, like infrared and white leds. and that it is always perfectly flat light. How do you control the exposure of red green and blue? With PWM or with the length of burst? On my applications I flash the led with the length of red green and blue being adjustible synced to the shutter of the camera. The advantage being I can use more powerful led without worriyng about heat. Also I get zero shake from the mirror/shutter and it is easier to implement HDR. Disadvantage is that it is more complex.

Peter J. De Smidt
30-May-2013, 04:56
We're using 60 RGB LEDs per meter ribbon:http://www.leevalley.com/en/hardware/page.aspx?cat=3,70322&p=70326

The controller is:http://www.leevalley.com/en/hardware/page.aspx?cat=3,70322&p=70327 We're using the one with three knobs.

ludvig friberg
30-May-2013, 05:40
Yes I have the same it is crazy bright! Here is the sketch I made to maximize leds per square mm. I am looking forward to seeing this in action.
96048

Daniel Moore
14-Jun-2013, 23:11
I realize this should go into the light sources thread but I'm going with the flow here. Ludvig or anyone else, do you have any ideas on how to make (3) three digit readouts for the R,G and B values work with this RGB LED Ribbonflex strip? So far I've heard from a couple of companies I've put that question to that it'll require a DMX controller, which seems like a replacement for the knob controller we're using for starters, no harm there as long as we can input values during the testing phase, until we can establish working presets. The stock controller is analog and I wonder if there's a converter/display type doodad that can help. The only thing I've found so far is a single readout DMX controller: http://www.chromationsystems.com/store/index.php?main_page=product_info&cPath=65_82&products_id=285&zenid=qfubgqfp2fom51r9k6c2rqjar6
I'm still working with Jeff from chromationsystems.com and will report any news.

I've also found this tidbit:

http://log.liminastudio.com/itp/physical-computing/arduino-controlling-an-rgb-led-by-hue
which represents another approach but that may be too much for the circuit as it stands, pretty much out of available pins without going to an Arduino Mega or similar.

ludvig friberg
15-Jun-2013, 06:03
Well if you want to control red green and blue with PWM from an arduino and control the light levels on r, g and b with digital control from 0-255 you could do it with three power transistors and one of these lcd shields with buttons http://www.adafruit.com/products/772. That would use up 5 pins. 2 for the display/button shield and 1 each for the R, G and B transistor. Also you could control everything else like speed on motors delays etc.

Ludvig

Peter J. De Smidt
8-Aug-2013, 08:42
Here's my XY stage before I cover everything with wires. It has 8" of movement left to right and 12" of movement front to back. The lighted area of the light source is 6"x8", which should be enough to scan 5x7" film. Building a light source for 8x10" was more than I wanted to spend on a prototype. Currently, there's a 12" x 12" piece of plate glass sitting up top. I'll be able to switch out a glass plate for wet scanning and P99 acrylic for dry scanning. Negative masks will be made from black ABS, and there will be stops so that it'll be easy to align the scanning surface and masks.

99860

Nathan Potter
8-Aug-2013, 09:05
Peter, that looks quite nice. I assumed you were using the light source under the glass but I don't see an aperture in the base so how does this function - especially with a large uniform 6X8 inch illuminator? Maybe I see a smaller aperture that is sufficient to cover only a full frame DSLR but is partially obscured by a stepper belt. The DSLR stays fixed over the smaller aperture? Those stepper belts seem to interfere with the illumination path.

Do you plan any stage leveling mechanism?

Nate Potter, Austin TX.

Peter J. De Smidt
8-Aug-2013, 09:43
Hi Nate,

Regarding the light source, here's the LED plate:

99870

It will be installed at the bottom of the white painted box, just above the belts. (Well, hopefully just above the belts. :) ) The interior of the light source, which is currently white, will be covered in reflective aluminum tape. (Tests show that doing so really helps with edge light falloff.) A 3/16" thick piece of white acrylic will sit in recessed opening.

Regarding leveling, rough leveling will be accomplished with 3/8" bolts. You can see them in the picture. I drilled and tapped holes in the thick maple slab for this purpose. For fine leveling, all major parts are bolted, often with t-nuts. As a result, shims can be installed in lots of places.

BetterSense
8-Aug-2013, 09:51
Why do you need/want the light source to be so large? If the X-Y table is going to move the negative around, then the even area of the light source only needs to be as big as the "shot" size, and it can hold still underneath the camera lens. What am I missing?

Peter J. De Smidt
8-Aug-2013, 09:56
You're not missing anything. It could be done that way, and that's what I did with an earlier prototype. I went this way, though, to minimize the chance of repeating patterns in the final stitch due to small irregularities in the light source, irregularities which would be repeated in each tile of the stitch.

Peter J. De Smidt
8-Aug-2013, 11:35
Z-axis:

99890

Randy Moe
8-Aug-2013, 11:46
Gives me ideas.

Not to do what you are doing.

Great sources, I will put them in the back of my night brain.

I have a lot of projects back there...

Interesting project guys!




We're using 60 RGB LEDs per meter ribbon:http://www.leevalley.com/en/hardware/page.aspx?cat=3,70322&p=70326

The controller is:http://www.leevalley.com/en/hardware/page.aspx?cat=3,70322&p=70327 We're using the one with three knobs.

Nathan Potter
8-Aug-2013, 12:07
Ahh, I missed the illumination technique. You are using the equivalent of a flat panel illumination system. That's handy from a design point of view and I see was commented on earlier as possibly being "crazy" bright. I suppose one could use a diffuser with such an arrangement if there was small local unevenness from the discrete LEDs. Pretty neat for compactness.

I have started to experiment with a similar design but will use manual X and Y translation with Edmund rack and pinion motion. I also am choosing, at first to use an Omega D2V enlarger condenser optics set (6 in. diameter) with a small halogen DC bulb that I drive from a regulated DC supply. So far I use an aperture to control the degree of collimation , (sort of a corrupted Kohler illumination technique). But this is of course bulky.

I find with the initial lashup (using an old Leitz macro copy stand for stability) that I can certainly obtain double the Epson V750 resolution using a good quality macro lens at 1:1. Increasing the contrast of the illumination certainly increases the MTF of the copied chromes. Also using a DC driven halogen bulb makes it possible to adjust the color temperature over a reasonably wide range.

I'm plugging along slowly at this right now being in the middle of two hip replacements.

Nate Potter, Austin TX.

Peter J. De Smidt
8-Aug-2013, 12:56
That sounds like a very interesting system, Nate. I look forward to hearing more about it, and seeing some pictures, down the road.

I agree that these systems can easily better a V750. That's possible even with a venerable 55mm micro Nikkor.

I hope that your hip replacements go well!

Peter J. De Smidt
8-Aug-2013, 20:50
While the current design has the belt drives close to the center of each axis, they don't need to be there. There is no problem with the stages racking wherever they are driven from. For instance, they could easily be driven with the belts outside of the parallel rails, leaving the center completely open.

marfa boomboom tx
19-Aug-2013, 08:43
Nice to see this project remains underway.. has the effort over the past year increased the ease, or raised the quality of the stitched/composited image?

is this effort making it faster, easier, higher in quality? (which of the set)

anyway, congrats for the preservation...

Peter J. De Smidt
19-Aug-2013, 09:21
Daniel might have any opinion about that, as he's had a working version for a few weeks now. Today, I'm going to install my light source, which might be a bit of a task. I should be able to run my first automated scan later this week.

Peter J. De Smidt
23-Aug-2013, 09:05
Here's the film stage with a mask for 4x5" film. The protective film is still on the P99 acrylic.

ludvig friberg
24-Aug-2013, 02:15
Looking good!
I am eager to see a video, pretty please with sugar on top?

Ludvig

Daniel Moore
24-Aug-2013, 02:25
An excellent idea! : )

Peter J. De Smidt
31-Aug-2013, 13:41
http://youtu.be/gmRHTausFls

Randy Moe
31-Aug-2013, 16:49
Works nicely!

Good job!



http://youtu.be/gmRHTausFls

Daniel Moore
31-Aug-2013, 16:54
It's a beautiful thing!

Peter J. De Smidt
31-Aug-2013, 18:14
Thanks. This wouldn't be happening at all if it wasn't for Daniel. He's put in a tremendous amount of time and effort to keep this project going, and his design is much more elegant than mine, especially for people who don't want to scan bigger than 4x5.

For the real deal, the lens would be masked really well, and there'd be black fabric keeping any ambient light off of the negative. I'm not sure, though, what lens I'll be using, and there are some other things to work out before getting to that.

Daniel Moore
31-Aug-2013, 18:34
Thank you Peter, but certainly half the credit for giving this project legs belongs to you. I was going to wait and get a few more details ironed out but will try and get a decent video of my rig in action posted asap.

Daniel Moore
1-Sep-2013, 23:24
For better or worse, here's my rig in action:

http://www.youtube.com/watch?v=PXy7RJwIBAo&feature=em-upload_owner

The Arduino program both Peter and I are running, Scanduino (https://github.com/nSomnius/Scanduino-by-ReallySmall), was written by Richard Iles, AKA Flickr member ReallySmall. It's based on his program Stackduino (http://www.flickr.com/photos/reallysmall/9177874726/) which we pinned him to the ground and gavaged him on house flies and mead until he got it repurposed for our needs.

Seriously though, his generosity in helping this project can't be measured, period. I ask that any program related questions be directed to me, my way of thanking him for his efforts, fielding questions to the extent I can. In other words, he's off limits and I'm the best you've got : ). I have learned a thing or two from him and I hope I can help.

As for our rigs, they are a work in progress. Yes, they work and prove the concept (and quite a bit more) and yes, they can be improved, and we're working on that, as we have for many, many, many months. Please consider them prototypes well worth one's effort to pursue. I hope (as Ludvig's version has inspired us months ago) to see yet more approaches. Mine for example, requires too much effort to produce, requiring access to very high end machinery, Peters, a quad bearing block/dual rail design, is far more flexible, especially regarding film format. These are decidedly early stages in this quest. With Mr. Richard Iles' 'Scanduino', by all means, go forth and multiply, and may the Z axis gods be always on your side.

Peter J. De Smidt
2-Sep-2013, 08:11
Outstanding, Daniel!

nonuniform
12-Sep-2013, 15:55
I'm in the process of spec'ing out a film scanner using linear rods like yours, but using a screw instead of belt drive.

What sort of hardware are you using the for the z-axis mount? I'm trying to figure that out now.


Z-axis:

99890

Peter J. De Smidt
12-Sep-2013, 20:24
101799A Velmex 4000 series unislide.

http://www.velmex.com/manual_cross_sections.asp?series=4000

nonuniform
13-Sep-2013, 13:06
I was wondering if that was a Velmex part. I had looked at their catalog thinking, hmmm, this might work!

Thanks for sharing all of this with everyone!


101799A Velmex 4000 series unislide.

http://www.velmex.com/manual_cross_sections.asp?series=4000

Peter J. De Smidt
13-Sep-2013, 13:24
Occasionally they come up on Ebay for a decent price. I bought mine there for $75 shipped. They are a very high quality device, much better than any of the photo specific devices that I've seen. The 4" wide series is nice for this use. For macro in the field, a smaller one might be more convenient. There are a choice of threads.

Peter J. De Smidt
13-Sep-2013, 20:03
Nonuniform, are you planing on using something like this: http://www.ebay.com/itm/12-NoMachine-1-2-10-acme-lead-screw-kit-CNC-router-delrin-nut-bearing-bracket-/141055385223?pt=LH_DefaultDomain_0&hash=item20d78e5e87 ?

Daniel Moore
17-Sep-2013, 22:37
If I waited for the inspiration to take decent images it'd be another year, so here are a few shots of my positioning system (notice how hard I'm trying to stay on topic?). : )

Many hours were spent trying to find a good solution to moving the film stage and I finally decided to take a chance on the IGUS Drylin rail/carriage system. I paid about 170.00 USD for two pairs of 330mm sliders. These are common amongst the video crowd and DIY'ers, to the point you can buy a set on Amazon. They are quiet and smooth, but not precise, that you have to pay for. But were they precise enough? The answer, after a few dozen scans, is yes. In practice the accuracy and repeatability of these sliders is remarkable. If you hold a set in your hand you can flex them easily along their track path. If you load it with 3.5 lbs of light source you can still flex it easily but it does not deflect all by itself it seems. I've mounted a custom GT2 belt clamp to the underside and pull them along and they work so well I'm shocked. I scanned a sheet of 4x5 film 5 times in a row and in photoshop compared the last exposure of the first run with the last exposure of the last run in difference blend mode and could not detect even a single pixel variation. So yeah, they seem to work well enough for this purpose.

Here's an image showing how I secured the two sliders mounted at 90° to each other with 4 screws. The carriage through holes are oversized and allow for fine adjustment to square up their travel relative to each other.

101990

Here's an image of the simple belt clamp which uses a strip of acrylic with a saw kerf in it at the right height from the bottom, a scrap of the belt engages the two cut ends and screws lock it in place. Also, you can see here how it was secured to the carriage. I drilled a couple of holes through the carriage and just a bit into the belt clamp plastic as starter points (two dimples in the plastic), then finished the holes (not shown) and tapped them to receive securing screws tightened from above. Note also how it does not matter that the free pulley and motor pulley are different diameters as the drive side is kept aligned along one edge, the other side of the belt free.

101991

The limit switches are secured to a custom mount made from plastic as well for now, they should be metal but this seems to work very well as is.

101989

As sloppy as this may all seem to some in practice the results are amazingly good and equally amazingly repeatable. Single pixel stitching errors as well as being able to replace one set of images with another and result in visibly perfect results are easily attained. I went out on a limb with approach and it's proving to be a very viable option.

Peter J. De Smidt
18-Sep-2013, 06:24
Thanks for the details!

nonuniform
23-Sep-2013, 17:26
Peter - I'm looking at something like this: http://www.ebay.com/itm/290776364520?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

I want the longer travel so that I can scan 8x10.

Daniel Moore
8-Oct-2013, 17:15
Finally got around to mounted my controls. Still need to cut 4 short dowels to extend the reach of the LCD menu buttons. I replaced the buttons on the Adafruit LCD shield with longer versions which reach to the back of the panel mount so the button extenders won't fall through.

103206

Peter J. De Smidt
8-Oct-2013, 17:16
Looks great! There's no way I'm showing my control setup.

Laron
23-Oct-2013, 09:37
I was just wondering (as I also had in mind to build one, just dont have the time of course...)
how about using our own cameras as a stand?
It would be so simple... easy/flexible to focus, precisely adjustable in all movements (of course), light-tight etc... what we all know well.
would only need a lensboard that accepts the dslr, and to the other side the film holder which can be moved (even horizontally if the whole thing turned like that) plus a light above. This top part seems like the only tricky thing, the rest is almost "done".
I guess you must had this idea Im just wondering why this is not working?
It cannot be stable enough?

Nathan Potter
23-Oct-2013, 10:14
Yes, stability is paramount unless you can shoot at a very high shutter speed. For a high shutter speed you need a bright illumination source in order to dig into the dense shadow areas common with some chromes (not so bad with B&W negs which have been carefully developed to minimize high density).

Electronic flash has been considered by some here and is quite attractive if intense enough to provide a short duration flash. Focusing optics could improve the intensity of electronic flash but also increases the contrast in the copy.

The other factor with stability is the DOFocus. It is vanishingly narrow at say 1:1 reproduction ratio so the slightest motion in the setup can move you out of best focus. Just simply to capture critical focus will require a precision rack and pinion or stepper device very rigidly mounted.

Nate Potter, Austin TX., Holliston MA.

Laron
23-Oct-2013, 12:49
thank you Nathan, I see now better.
thats a pity we cannot benefit of what we already have.
Actually I have "built" a test version of this setup but so far only for capturing 35mm format, it worked out quite well but I was not sure this can be developed further to 4x5.. I had the same impression this might fall out because of stability problems. Also true I was capturing around 1 second each exposure at f16 thats quite long. I was using a canon 5dm2 with desktop exposure control, it was nice to focus with the live view at 100% on a big screen, though was very noisy because the high iso.
As the camera can hold stable to expose for minutes (or hours) - as we do our images with this first on the film itself- so I thought why not be as stable the opposite way?
Anyhow for me it worked for single 35mm slides, but probably there would be issues with a big moving thing on top for a 4x5 capture...

marfa boomboom tx
16-Dec-2013, 11:36
And for non price theory info thread:



http://www.instructables.com/id/Low-cost-digital-microscope-with-automated-slide-m/

another general version of the means and method of stitch scanning.
Although, I expect, anyone seriously making one, has already done so.