DSLR Scanner: Lenses

[Peter J. De Smidt]

DIYS (Do It Yourself Scanner—pronounced like ‘dice’)--Lenses 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 lenses here soon.

[Peter J. De Smidt]

Here's a nice test of some lenses of interest: http://www.macrosmuymacros.com/index.php?option=com_content&view=article&id=27&Itemid=40&lang=en

[Peter J. De Smidt]

Here's the whole 6x7 negative:

http://i955.photobucket.com/albums/ae37/peterdesmidt/Light_House_2nd_Manual.jpg

Just for fun, here's the results for a 4x microscope objective.

http://i955.photobucket.com/albums/ae37/peterdesmidt/ZS_4x-1.jpg

That's the whole field captured downsized to a reasonable web size.

Next we have a screen capture of a small part of the file at 100%:

http://i955.photobucket.com/albums/ae37/peterdesmidt/sc_100.jpg

[rdenney]

What lens did you use for this one, Peter? Was this the Micro-Nikkor with extension tubes to achieve 1:1?

Rick "who hasn't yet experimented with the Canon Compact Macro with the new (to me as of Friday) life-size converter" Denney

[Peter J. De Smidt]

It's an AmScope PA4X, marked: Plan 4/0.10/160/0.17

The '4' is the lateral magnification. The '0.10' is the numerical aperture. The '160'mm is the tube length, i.e. the distance from the camera sensor to the back of the lens, not counting the threads, and the '0.17'mm is the expected cover glass thickness.

It was this one: http://www.ebay.com/itm/350123872902?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

It's a cheap 4x that the macro folks like.

[Nathan Potter]

Peter, it appears that the magnification factor is about 20X between the 4X5 and the second image. I assumed you've imaged the grain which is what shows in the second shot then simply magnified it more (about 4X) in the third shot.

What is interesting is no sign of vibration in the capture - a key advantage of using flash in high magnification situations. Contrast seems pretty darn good which is notable for an inexpensive microscope objective.

What was your reason for doing this test? There would be hundreds of frames needed to replicate a whole 4X5 image but clearly the result would equal the best drum scanner. So is this an existence theorem?

Nate Potter, Austin TX.

[Peter J. De Smidt]

Oh, I've had the lens for a little bit, and I just figured out a way to mount it today. The quality will get better when my Prostar flocking material arrives soon. (http://www.fpi-protostar.com/flock.htm). The current extension tube is shiny black on the inside. Using such a lens would be absolutely overkill for 4x5, but it might be useful with 35mm, or perhaps even medium format.

[Peter J. De Smidt]

I just did a comparison between the 75mm Linos mounted forward and my Nikon 55mm mounted in reverse, both at 1+1. In that configuration the Nikon performs better. I'll try mounting the Linos in reverse, but that will be a bit of a pita.

[rdenney]

I just did a comparison between the 75mm Linos mounted forward and my Nikon 55mm mounted in reverse, both at 1+1. In that configuration the Nikon performs better. I'll try mounting the Linos in reverse, but that will be a bit of a pita.

I was afraid that would be the case. When I compared it to the EL-Nikkor, it wasn't quite as good.

Rick "who had hoped for a chance to work on it today, but ended up grouting bathroom tile" Denney

[Peter J. De Smidt]

Preliminary tests show that at 1:1 the Linos is better reversed than forward. Whether it's better than the Nikon is hard to judge, and will require more thorough testing.

[buggz]

Here is a site w/ more info about this subject:
<<http://theonlinephotographer.typepad.com/the_online_photographer/2012/01/how-to-scan-film-2.html>>

[Peter J. De Smidt]

Today I tried a 50mm Componon-S reversed. The results are pretty good. It's hard to compare results, though, as everything needs to be the same, especially magnification, and that's tricky.
For the time being, I'm going to leave off lens testing and look into automation.

[Donald Miller]

I have followed this thread with interest. There is a lot of good information contained here. I have a question that I don't have the answer to. For that reason I am posing it here. I have a Canon 65mm dedicated macro lens. This is the lens that can not be used for normal pictorial use (macro only) and will render at 1X up to 5X magnification. How would this degree of magnification compare to a drum scan? A good educated guess of the comparison will determine if I go forward to design a system to use that lens in a scan capacity with either my 5D MkII or 1DS Mk III. I have a Novoflex Cross Q focusing rail for two axis (X and Z) that I would like to incorporate. My other problem, should I decide to go forward with this, would be the third (y)axis. Thanks for sharing your thoughts on this.

[Peter J. De Smidt]

Hi Donald,

That lens has a very good reputation. It'll allow you to use live view and focus from your computer, which should be very helpful. Earlier in this thread, I show a close up from a 4x microscope objective. Your Canon lens should be able to just as well. Actually, I expect it to do better, seeing how it's a $30 lens versus a $900 one. (The macro folks say that there's no advantage to microscope lenses until you get above about 6x magnification.) The microscope lens captured better detail than I did with my Cezanne. But at 4-5x, you'll need a lot of frames to cover a negative, especially a large format one!

Detail wise, I expect that we can get very close to the resolution of a drum scan, but that's not the same thing as saying we can get the same quality. As Peter Ramm mentioned in the main thread, the big difference between a drum scanner and what we're doing is flare. What this means, I expect, is that the drum scanner will be able to see more distinct tones than we'll be able to get with our scanner, no matter how careful we are with masking off of spill light. Is the difference enough to matter? I don't know, and it's a subjective judgement in any case.

Ideally, you should get one of your negatives drum scanned so that you can compare. You can then take a close up with a simple dlsr rig of just one exposure to see how it compares. There wouldn'd be a need to do any stitching at that point. If you don't get the quality you need with that one square, you won't be able to get what you need by combining a bunch of them together. If the quality is acceptable, than you have proof of concept that the endeavor would be worth while.

I'm not sure how you plan to use the Cross Q. If you explain a bit maybe I can make some suggestions.

[Nathan Potter]

I have followed this thread with interest. There is a lot of good information contained here. I have a question that I don't have the answer to. For that reason I am posing it here. I have a Canon 65mm dedicated macro lens. This is the lens that can not be used for normal pictorial use (macro only) and will render at 1X up to 5X magnification. How would this degree of magnification compare to a drum scan? A good educated guess of the comparison will determine if I go forward to design a system to use that lens in a scan capacity with either my 5D MkII or 1DS Mk III. I have a Novoflex Cross Q focusing rail for two axis (X and Z) that I would like to incorporate. My other problem, should I decide to go forward with this, would be the third (y)axis. Thanks for sharing your thoughts on this.

Best to wait for some results from others here who are actually building a setup and may use that very camera. But the optical and capture hardware you mention is pretty well known. The pixel pitch of the 5DMKII is about 6.8 um and I would imagine that your macro lens has resolution with reasonable contrast in the 50 to 75 lp/mm. (10 to 7 um airy disk pattern) range.

Given these figures you can assume that you should get a scan resolution of about 2500 to 3500 SPI. This is of course subject to the whims of the digital processing within the camera as well as the illumination source and light scatter reduction scheme. Mechanical issues particularly such as focus maintenance will be important.

To achieve the high resolution that is endemic with the setup you mention the focus maintenance is particularly onerous. At f/2.8 for instance and a COC of 7 um (compatible with the 5DMKII pixel pitch) the depth of focus would be about 40 um (a bit under 2 mils), and needed over 5 inches.

But in fact this far exceeds the resolution of the image you are likely to get on 4X5 film. What you will be sampling will be the smooth tonal values from overlapping circles of confusion with in the film emulsion, which may be of considerable benefit in the replication process. Done carefully I suspect you will approach the quality of some drum scanners. Keep checking here.

Nate Potter, Austin TX.

[Donald Miller]

Thanks Peter and Nathan. Much appreciated.

[marfa boomboom tx]

It still breathes --

for those concerned about lens distortions:


adobe (2010)
http://download.macromedia.com/pub/labs/lensprofile_creator/lensprofile_creator_cameramodel.pdf

Others:


http://forums.adobe.com/message/3382077


http://developer.berlios.de/forum/forum.php?forum_id=27253

http://www.agisoft.ru/products/lens/


http://lensfun.berlios.de/lens-calibration/lens-calibration.html

http://publiclaboratory.org/wiki/mapknitter-correcting-lens-distortion

======
Just a reference note, check out LCC concept used by most high Res MFDB users --

http://help.phaseone.com/en/CO6/Editing-photos/Lens-Correction.aspx


&off

[Peter J. De Smidt]

Thanks for the links!

The ones that I've check into have you take a picture of a fairly large scale target. Do the lens characteristics change significantly when moving to 1:1 magnification?

[marfa boomboom tx]

Thanks for the links!

The ones that I've check into have you take a picture of a fairly large scale target. Do the lens characteristics change significantly when moving to 1:1 magnification?

What most of these discussions are over is the building and maintenance of a database of lens characteristics. The reason for the target size is to get infinity focus, since that is the more likely use of the data. A picture of something distant. It also permits the target to be less precise (no depth, just x & y).

The LCC plate (1/8 thick white plastic 3" sq) works quite well at making corrections in the land of $40,000 setups.

I submitted these links for the folks coming along in 2 years, who will have different equipment and needs. So they can laugh at our rustic methods of today.

The lens distortion database, in the above links, is being used to bring images together from a wide range of original lens images. Meaning, 3 people go out and shoot, using very different cameras, yet the map folks have to combine the work into one image.

The theory of correcting lenses is the same for them and for us. You could create a database and then shoot image after image, or (what I do) shoot an LCC (with rulings ) at the start of the scan cycle, then shoot the scan-shots.

The LCC is applied to each shot in the set(I use 15 for 4x5). Then those images are combined and written as the final reconstructed original.

&off to SF for SPE

[jb7]

Struan Gray, on page 55 of the main DSLR Scanner thread, introduced a number of new ideas, including using a Telecentric lens.
I was quick to remind him of the danger of over-complicating the process, and that I would never consider buying yet another lens of such limited usefulness- never mind the risk that it might not conform to our necessary specification, without having any way of knowing, before making the purchase.

And that I have to break the habit of buying even more pricy pieces of glass.

I've recently been told that I buy glass the way ladies buy shoes, which kind of focusses the issue...

So, with that out of the way, I went out this afternoon, and bought a 55mm f/2.8 Macro Computar Telecentric.

The specifications didn't look promising, 11mm image circle, and a c mount.
However, when I got it back, I found that it lights up a full frame with only tiny bit of darkening on the corners- and that's holding the lens up to the F mount, without allowing for the additional mount I'm going to have to come up with. It's also at it's minimum magnification, which images a field of view about 6cm wide.
It focuses from there, to beyond 1:1.

So, I had thought I'd have to use it on a crop sensor, but it seems there might be more options.

There are no reviews I could find, but there are basic specifications here- http://computarganz.com/product_view.cfm?product_id=561

The lens is advertised as having minimal distortion- and a quick look through shows a bright contrasty image, and it looks straight enough-
However, I don't think I'm going to be able to test for about a month- it'll take a little while for the mounting bits to arrive from China, and I'm off to NY in ten days time, for a few weeks.

But it looks promising-
and goes to show how open to suggestion I am, as Frank and Struan can verify...

[Peter J. De Smidt]

So, with that out of the way, I went out this afternoon, and bought a 55mm f/2.8 Macro Computar Telecentric.


That's hilarious! Before opening up the thread, I never would've expected it.

I look forward to seeing your results. Computar made some outstanding enlarging lenses, as well as some excellent LF optics.

[Struan Gray]

So, with that out of the way, I went out this afternoon, and bought a 55mm f/2.8 Macro Computar Telecentric.

Ha!


Still, it's cheaper than the Zeiss 100 f2 by a significant margin.

[rdenney]

A bit of lens testing:

I'm still comparing my Canon 50mm Compact Macro, with the 1:1 converter, against my previously tested EL-Nikkor 105. The Canon has a significant advantage--autofocus confirmation.

But the shorter macro lens suffers from excessive fall-off, in the range of about 15%, at all apertures. I suspect this is a combination of the shorter focal length and the response of the sensor. The Nikkor's falloff is more like 3-5%. I've written in the light-source thread that I'm using an LED-backlit computer monitor panel to provide the backlight, and it's very even in an of itself. Using that for a light source also provides the means create a correction pattern that can be displayed on that monitor. More experimentation needed there, but I'm expecting that to be fairly easy. The panel is parked well behind the film being scanned so that it's pixel pattern is completely out of focus.

One test I used to determine lens performance: The size of the resulting files. I could not tell by inspecting the files of a normal negative which aperture was the sharpest, but the JPEG files sizes were: 3361, 3757, 4402, 4064, 3498, and 3225, for f/5.6, 8, 11, 16, 22 and 32, respectively. This outcome is nicely monotonic, peaking at f/11, which is completely reasonable. The EL-Nikkor file sizes ran about 15% higher than the Canon macro sizes, which were also nicely monotonic, peaking (unhappily) at f/22. That the Canon lens needed such a small aperture was not a positive statement in its behalf--aberrations took a lot of correcting before diffraction overcame them.

Remember that my camera is a 12.5MP Canon 5D when judging these files sizes. Raw files were in the 13-14 MB range, followed the same curve and were proportional to the JPEG file sizes.

Looking at the best of these files, which was the f/11 file for the EL-Nikkor, I see that the scan is not sharp to the pixel. Dust specs on the negative, which show up as white after inversion, have edges smeared over two or three pixels. They are sharper than the image on the negative, which I take to be limited by the photograph itself, though I was able to make very sharp 16x20 prints from this negative back when I had my darkroom. The taking lens was a Schneider Super Angulon 121mm f/8 at f/32. The original image is posted here. (http://www.largeformatphotography.info/forum/showthread.php?77076-Doors-and-Doorways&p=834903&viewfull=1#post834903)

I don't think I'm doing any better than the Epson than I was with my first quickie test, to be honest. I still cannot resolve beyond a hint of grain.

This picture is the whole 24x36 scan frame:
71093

Here is a 100% detail (or it will be after you click it). The staple is about 1mm on the 4x5 negative. I've adjusted levels and curves to match my conception of the image (as linked above), but this is without any sharpening.
71094

Here it is with a bit of sharpening to overcome the effects of the anti-aliasing filter on the camera. The sharpening setting is 0.6 radius, amount 200, zero threshold. I can just see a hint of grain, maybe. The detail in the negative isn't, I don't think, sharp enough to benefit much from sharpening at this level, but this is basic corrective sharpening, not the sharpening I might do when targeting the image to a particular print size.

71095

Maybe this is just as good as my 5D can do at 1:1. Or maybe I just need a better lens.

At least there's no distortion. I photographed a clear plastic ruler, and drew a line along the edge. At the resolution of my camera and lens, the edge was straight within a pixel along its entire length.

Rick "taking baby steps" Denney

[Peter J. De Smidt]

You might try downloaded Zerene stacker, http://zerenesystems.com/cms/stacker, which has a 30 day trial. Get the focus at the confirmation spot. Now back off the Velmex a small bit, about a 90* rotation. Take a series of photos, moving the velmex knob about 10* with each step. Go past the confirmation point by a good number. Bring the images into Zerene and run a Dmap stack. Now compare the image to what you took with a single frame. This will not only get rid of any focusing error, it will also help if the lenses' plane of sharp focus isn't really planar, and it'll alleviate any misalignment issues.

[rdenney]

You might try downloaded Zerene stacker...This will not only get rid of any focusing error, it will also help if the lenses' plane of sharp focus isn't really planar, and it'll alleviate any misalignment issues.

My next step is to check focus by running some tests, and that may entail a series of photos with small slide movements. But I don't think I need to go as far as focus stacking. Nothing I've seen suggests any misalignment--the image is uniformly sharp edge to edge. It's just hard to focus that camera that critically with a manual lens. I'm trying again with an eyepiece magnifier, and if that doesn't help, I'll make a series. With that Velmex slide, the minimum effect I can almost see is 180 degrees of the handle. The Canon auto focus narrowed that to about 45 degrees. I will also try a different adapter with Canon electronics in it, though I'm not sure that one is correctly clocked and camera ends up not quite level side to side.

Rick "back to the basement" Denney

[Nathan Potter]

Rick, I wonder about the difficulty of aligning the plane of the sensor to that of the film. Maybe it would be possible to make use of a cheap laser pointer. How about shooting the beam through the film mounting glass and reflecting it off a mirror taped to the front of the DSLR lens. Then adjust the DSLR plane to shoot the beam exactly co-linearly back through the film plane. A bit of fussing with this, but if the DSLR lens axis is precisely orthogonal to the sensor (high quality DSLR should be I suppose) then you should have a pretty good alignment. As I recall in your setup you may not be using a glass plate for film mounting - but maybe you could substitute one. The laser pointer would be temporarily substituted for the normal light source. Just thinking about alignment issues when I start fiddling with this.

Nate Potter, Austin TX.

[rdenney]

Okay, experiments have continued.

The focus was correct with the EL-Nikkor. I made a series of exposures and looked at each of them at high magnification, and I had to turn the Velmex handle a whole turn (0.025") to noticeably degrade the image at f/11 (indicated, f/22 effective) and 1:1. Everything in the range of +/- 0.015", at the very least, looked identical. So, I stopped worrying about focusing. I just focused one way until the the image, blown up on the camera's LCD, was noticeably less sharp, turned it the other way past focus until I got the same result, and then split the difference. Just like I used to do with the enlarger.

I also set the camera to lock up the mirror, pause three seconds, and then open the shutter, using a remote cable. Made no discernible difference at any shutter speed.

What was not correct with the EL-Nikkor was the EL-Nikkor. It's okay, but I doubt it's optimized for this magnification. And it's just a wee tad long to get much greater magnification with my setup. And my Canon macro lens only goes to 1:1.

So, I tried something different. I took a cheapie 80mm f/2.8 Arsat lens, put it on an Arsat reversing ring, and mounted it on my bellows arrangement reversed. The Arsat has a 62mm filter ring--not common--so that's the lens I have that will fit that reversing ring. I had bolted my bellows standards down onto an Arca plate, so I just slid the whole thing forward, focused it, and made some photos. Magnification is greater--about 1.8:1. The reversing ring provided considerable additional extension, as it turned out. So, the field of view is 13mm by 20mm. I can pretend I'm using my wife's D300, heh.

For the curious, the Arsat is a 6-element double-gauss lens, multicoated, and a good performer used normally except at apertures larger than f/5.6. It is, of course, a medium-format lens intended for 6x6, and this application is just using the sharpest part in the middle of the field. In this case, the greatest detail was recorded at f/11 according to the file size, but I could not see any improvement over f/8. f/5.6 was visibly worse, as was f/16.

And there is the grain. Once I could see grain, I decided to exaggerate the sharpening, partly to demonstrate Ben's point. So, I used a radius of 0.7, a threshold of 0, and an amount of 500. Dust spots on the negative became crisply resolved to the pixel, and I think I'm now getting everything there is to get from the sensor. Note that what made this possible was seeing grain--seeing grain allows radical sharpening, because the sharpening is increasing the apparent acutance of the grain. Given that there is no signal at that scale, it does not increase the signal/noise ratio at larger scales. Sure enough, even viewing the 13x20mm piece of the original negative as a single image does not show anything untowards with that much sharpening at the grain level.

This suggests to me that a key to this approach is providing enough magnification or resolution to resolve grain well enough to be able to really apply sharpening to it. That improves the MTF at larger scales without the grain becoming more apparent. But if you look at the image at much greater than 100% on the monitor, it will look a bit freaky.

Comparing this image with the one from the EL-Nikkor is interesting. The EL-Nikkor resolved some grain--there are larger grain clumps visible in both images--but not enough to allow that sharpening strategy without it revealing artifacts at larger scales.

So, instead of making multiple 1:1 exposures to reduce noise, my intention is to make the same number of exposures overall, but smaller tiles instead of redundant tiles.

Here's the 13x20 sample (on my monitor, the image, when you click below, is a piece of what would be a 24x30" print):
71117

And here is the detail at (if you click it) 100%--a 50x enlargement if your monitor has 100 pixels/inch:
71118

Both are post-sharpening.

Rick "making progress" Denney

[rdenney]

Rick, I wonder about the difficulty of aligning the plane of the sensor to that of the film.

I don't have an alignment problem. The film seems to be pretty exactly parallel to the sensor--there is no difference in sharpness across the frame.

Don't be confused by the apparent distortion--the door on the front of the Espada Mission does not have one single right angle on it, and the photo itself was not corrected for laterl perspective convergence. Since the subject was not parallel to the film when the negative was exposed, there is a touch of change in apparent sharpness across the face of the door. I was also trying to keep the stone door frame in acceptable focus--the shapes of those stones are the design point of that doorway. I'm evaluating sharpness mostly using dust spots and grain, as best I can.

Rick "noting that the camera axis is normal to the film holder within a thousandth or two over a little more than a foot" Denney

[Peter J. De Smidt]

Some lens tests: http://www.coinimaging.com/Lens_tests.html

[rdenney]

Some lens tests: http://www.coinimaging.com/Lens_tests.html

Sorta makes me want to find an old Micro-Nikkor. I've looked a few times, but I haven't found the right deal.

Rick "who owns too many lenses already" Denney

[Peter J. De Smidt]

Rick, I wonder about the difficulty of aligning the plane of the sensor to that of the film. Maybe it would be possible to make use of a cheap laser pointer. How about shooting the beam through the film mounting glass and reflecting it off a mirror taped to the front of the DSLR lens. Then adjust the DSLR plane to shoot the beam exactly co-linearly back through the film plane. A bit of fussing with this, but if the DSLR lens axis is precisely orthogonal to the sensor (high quality DSLR should be I suppose) then you should have a pretty good alignment. As I recall in your setup you may not be using a glass plate for film mounting - but maybe you could substitute one. The laser pointer would be temporarily substituted for the normal light source. Just thinking about alignment issues when I start fiddling with this.

Nate Potter, Austin TX.

I use a Versalab Parallel to do exactly that. It works a little better over longer distances, but it's still a big help.

[Peter J. De Smidt]

Rick,

I agree with your conclusions regarding grain.

Ideally, we want a lens that performs best at between f4-f8. We should be able to find that. Reversed enlarging lenses often perform best at 4-5:1, which is more magnification than we want.

[rdenney]

Okay, I just bit the bullet at KEH, and bought an 55/3.5 Micro Nikkor (I got the Ai version, though I know the previous version has some interesting qualities, because it needs to work on my wife's D300), the correct Ai extenstion tube (Pk13), and also an old pre-Ai M tube. Oh, and a reversing ring. So, if I have to keep my magnification greater than 1:1, I can reverse the lens and add the additional ring. These lenses have always attracted magical reverence--I hope this one lives up to it. $133 total for all of the above--still a fraction of the price of that Computar.

Rick "who probably should get another Nikkor adapter for the Canon" Denney

[Peter J. De Smidt]

That's a newer lens than mine. It should be a very good performer.

Make sure to check the various adapters for shiny surfaces, and it might help to make a baffle out of flocking material to put inside the extension tubes. If you need a small bit of flocking, let me know the size, and I'll send you a small bit. A diy lenshade with an opening only a little bigger than the image area would also help.

[rdenney]

That's a newer lens than mine. It should be a very good performer.

Make sure to check the various adapters for shiny surfaces, and it might help to make a baffle out of flocking material to put inside the extension tubes. If you need a small bit of flocking, let me know the size, and I'll send you a small bit. A diy lenshade with an opening only a little bigger than the image area would also help.

My collection of Russian and Ukrainian cameras demands that I own a good-sized stock of flocking paper, heh.

The Micro-Nikkor is a good addition to my tiny collection of classic Nikkors, bought for their classic status and excellent current price. I have the 105/2.5 and the lovely 180/2.8ED. And the Nikon Series E 70-150, which is an amazing lens for being a cheapie, even though I don't do much with it. I've wanted the Micro since about 1975 when a buddy of mine bought one and I saw the pictures he made with it.

Rick "looking forward to trying it out on this project" Denney

[rdenney]

That's a newer lens than mine. It should be a very good performer.

The Micro-Nikkor arrived today, and it's a nice old f/3.5 Micro-Nikkor of Ai vintage--late 70's. Optics were perfect. Also arrived with the PK13 extender and a BR2 reversing ring.

My initial test was at 1:1 with the extender. F/8 was again the sharpest aperture. F/3.5 showed obvious softening at the edges, and even f/8 didn't fully correct that. I was surprised, to say the least. But I can only assume that the field is not quite as flat at 1:1 as it is at 1:10, which is probably where this lens was really optimized.

At 1:1, the Canon 50/2.5 Compact Macro and Life-Size Converter out-performed it. The center was the same, but the edges were very much better with the Canon. Again, I was surprised. I'm not sure I should have been, though, since I'm not usually subject to the Nikon Kool-Aid. The old Micro-Nikkor is a double-gauss design with five fixed elements, and the Canon lens is a 7-element double-gauss design with two additional corrector elements that are fully floating. And the life-size converter is not an extension tube but a specially designed 4-element optical converter specially made for this lens. As Kingslake would say, it has many more degrees of freedom in the design. But the Nikkor is still better in terms of falloff where the Canon lens does poorly, which is a limitation in this application.

But one cannot reverse the Canon or add extension tubes--Canon would rather you buy their specialty macro lens for greater than 1:1. Given that I'd gotten better results with a cheapie 80mm normal lens reversed on bellows, I took the Nikkor and reversed it on the extender. Reversing it moves the glass much further away, so with the extender, the magnification was about 1.5:1--not quite as much as I'd gotten with the reversed 80mm lens. It has about the same field of view as a APS-C (DX in Nikon-speak) sensor at 1:1. An important advantage to being used this way is that I get more magnification than I can get with the Canon, but still in a lens fast enough to provide an autofocus confirmation (with my electronics-equipped adapter). I found the focus confirmation to be dead-on accurate at f/3.5, and then I stopped down manually. Reversed at 1.5:1, and at f/8, the Micro-Nikkor was completely sharp to the corners and rendered grain, though a touch more softly than the reversed 80mm lens. But I was still able to sharpen radically at a sub-pixel radius and still get quite smooth images at viewable sizes. This will be my working setup, I think. It's not really any sharper than the reversed 80mm lens on bellows, but the provision of a working focus confirmation tips the scales.

The reversed Micro-Nikkor has another really nice feature. The rear of the lens has a rectangular opening as a mask for the lens when it's racked out in normal use. I can use the focuser to extend the rear of the lens out as far as I like when reversed. It makes a very efficient shade that can be nailed right down to the edges of the field of view. That's a good thing in this application.

Rick "who now thinks the 5D AA filter is the limiting factor at 1:1" Denney

[Peter J. De Smidt]

I took my samples for the lighthouse picture with the Nikkor reversed at 1:1 magnification, confirmed by photographing a mm scale. (I used an extension ring too, I can't remember which one.) I used F5.6. The big difference is that my camera has a DX sensor.

[rdenney]

I took my samples for the lighthouse picture with the Nikkor reversed at 1:1 magnification, confirmed by photographing a mm scale. (I used an extension ring too, I can't remember which one.) I used F5.6. The big difference is that my camera has a DX sensor.

Must be a short extension tube, not the 27.5mm tube that is intended for 1:1 use with the lens not reversed. I think it's about 1:1.5 reversed and mounted directly on the camera, and 1.5:1 on the PK13 tube.

The smaller sensor makes a big difference in a lot of ways. I now also know how you got such even illumination, heh.

In the center, there was no observable difference between f/5.6 and f/8. But the difference in the corners was definitely observable.

Just to be goofy, I'd like to try my P67 135mm Macro-Takumar. It's a dialyte design, apparently pretty symmetrical. But I don't have a way to mount it just yet, and whatever I use has to be strong--that's a big, heavy lens. I had it out today and pondered it--I need it this weekend for another project. I'd probably spend my time better by mounting that Magnagon, heh.

Rick "doing some art copy work this weekend, on digital and on film" Denney

[Peter J. De Smidt]

Yep, the tube was a short one, one of Nikon's old 'K' sets.

One key to even illumination is to make the light source significantly bigger than the negative. I found that out when doing some masking on my Cezanne.

[rdenney]

Yep, the tube was a short one, one of Nikon's old 'K' sets.

One key to even illumination is to make the light source significantly bigger than the negative. I found that out when doing some masking on my Cezanne.

I'm still using my "computer monitor" LED light source--much bigger than the even the negative being scanned. Yes, in a diffusion source, the light has to hit each part of the negative being scanned from all of the same angles as all other parts. The laptop display is pretty blue, but okay for testing at this point. When I get around to it, I'll task an old display with the job and see about making some correction files. Clearly, the falloff I'm seeing is related to the sensor in my camera, and influenced by the lens. Testing that has made me realize just how dirty my sensor is, too.

I'm thinking that 1:1.5 would be just about perfect, though, for digitizing old 35mm color slides on a DX camera like my wife's D300.

Rick "who can get to about 2.5:1 with this rig" Denney

[Peter J. De Smidt]

I am going to be very interested to hear how your Takumar performs.

[rdenney]

I am going to be very interested to hear how your Takumar performs.

Ha! Don't hold your breath. That old, all-metal 135/4 Tak is weighty, providing coverage as it does for 6x7. A reversing ring might be necessary--I've never found anyone who can ascertain at what magnification the lens was optimized for. Apparently, it was optimized for close-up--there are many reports (some of which may be repeating each other--Struan's crowd-source) of the lens doing less well at infinity. Probably, it is optimized for something like 1:10--it doesn't even make it down to 1:3 without tubes. I have the tubes, but not the reversing ring or the adapter. I've seen the adapters, but they are sort-of expensive, though they do have what is probably an inadequate shoe. I'd have to adapt a Bogen long-lens support, probably. I wouldn't want to hang that lens off my 5D unsupported, especially on tubes.

Now, if someone would buy me a Pentax 645D, then my priorities would shift immediately, heh. 1:1 on a 33x44 sensor would require fewer tiles!

Rick "accepting donations" Denney

[Peter J. De Smidt]

Here's another link to some lens tests: http://savazzi.freehostia.com/photography/apo_componon_60.htm

[Peter J. De Smidt]

And some more interesting tests: http://www.photomacrography.net/forum/viewtopic.php?t=16608&start=15

[Peter J. De Smidt]

Here's a link to a layered tiff that shows a 55 nikkor forward, reversed, led source, and a flash source: http://dl.dropbox.com/u/3595413/55mmMicrotests.tif The magnifications are very close to 1:1, although there is a slight difference between the forward and reverse magnifications. The image is of a 24mm long section of a 4x5" TMX negative developed in Pyrocat MC.

[ludvig friberg]

I think they look good all of them, they all clearly resolve the grain in the film. Its hard to judge color spectrum differences on the different lighsources on black and white though. What would be a good test image to shoot for color? I have a Epson printer(4900) that has very large gamut. I was thinking of printing some kind of test and shoot on Porta and scan that as best as I can on my coolscan and use as a reference. Then try to see how close I can get with different lightsources on dslr. What would be a good testchart, testing color and sharpness?

Ludvig

[Peter J. De Smidt]

I wouldn't judge color on any of them. The color of the stained film is very brown. Each file was white-balanced in Light Room. I doubt the my low CRI led source would be ok for color. The best test for color would be an IT8 slide. Wolf Faust sells them cheaply.

A good test chart is any flat film that was sharply focused. You can use fancy USAF resolution testings slides, or similar, but they are expensive.

[Peter J. De Smidt]

While this lens is way overkill for the scanner project, some of the people interested in the scanner might also be interested in general macro work. There's a very good deal on a JML 20x finite objective. It's about $45 shipped. See: http://www.ebay.com/itm/JML-Optical-20x-Objective-w-Casing-MANY-AVAILABLE-/200718941277?pt=LH_DefaultDomain_0&hash=item2ebbc7fc5d For some discussion of these lenses, see: http://www.photomacrography.net/forum/viewtopic.php?t=16171&postdays=0&postorder=asc&start=75 Note that at this magnification focus stacking would be required for any useable depth of field.

[Old-N-Feeble]

While this lens is way overkill for the scanner project, some of the people interested in the scanner might also be interested in general macro work. There's a very good deal on a JML 20x finite objective. It's about $45 shipped. See: http://www.ebay.com/itm/JML-Optical-20x-Objective-w-Casing-MANY-AVAILABLE-/200718941277?pt=LH_DefaultDomain_0&hash=item2ebbc7fc5d For some discussion of these lenses, see: http://www.photomacrography.net/forum/viewtopic.php?t=16171&postdays=0&postorder=asc&start=75 Note that at this magnification focus stacking would be required for any useable depth of field.

Damn... I won't open a PayPal account (hate hate hate), the auction states PP only, and the seller won't reply to questions.

[Peter J. De Smidt]

As per their auction: "Need to contact us? Please use the eBay message system under the "contact seller" hyperlink. We receive many emails each day and strive to answer them within 24 business hours. We rarely exceed 48 business hours when responding to emails. " He's been very responsive to others on the macro list.

[Old-N-Feeble]

Peter... That's what I did but the seller has that disabled. I received an auto-reply stating "...unfortunately the seller cannot reply..." blah blah blah.:(

[Peter J. De Smidt]

If you go to the <About the Seller> link, it'll take you to a page that lists their email address along with a live chat option.

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

[Old-N-Feeble]

Thanks, Peter. I sent them an email.

[Peter J. De Smidt]

Make sure you read the macro forum posts about the lens. At that magnification, it's very specialized. Without the ability to do focus stacking with less than 10 micron steps, you won't get very good images. With a dlsr scanner, it would mostly be useful for film/developer tests, where the idea would be to capture one tile of the film, as opposed to covering the whole negative, which would require a huge number of tiles. That said, how an image looks when printed at it's final size is much more important than how the film looks under a microscope.

[Old-N-Feeble]

Peter... Since it's optimized for 20x I was hoping it would perform well at 4x or so but that may not be.

[Peter J. De Smidt]

Peter... Since it's optimized for 20x I was hoping it would perform well at 4x or so but that may not be.

I doubt that it would be any good at all at 4x. If that's the goal, there are some better options. I posted some examples from an inexpensive 4x objective and some info in posts 3 and 5 of this thread.

None the less, for general scanning use, something like a standard 60mm macro, especially one that goes to 1:1 with autofocus, would be by far the easiest to use. Ideally, you'll be able to focus from a tethered computer. If you go much above 1:1 magnification, you'll need to use focus stacking for good results, and that greatly increases the complexity and cost of the project. For large format work, it would also be overkill.

[Old-N-Feeble]

Thank you, Peter. I need to take more notes so I can keep up. :)

[Old-N-Feeble]

I saw the following lens on the 'bay but didn't bid on it because I had other plans for my money and I don't know anything about it. My guess is one like it could be very promising.

The title begins with "Kodak Printing Ektar 103mm" and it's a recently completed auction.

[SURF]

I have tried to make a picture of the USAF resolution target with a Canon D450 (12 Mp), extention rings and some lens. It worked. The size on the target was about 24 mm x 16 mm. Was possible to get at least 3600 dpi (see the 400% crop). Really not bad.80459

[Peter J. De Smidt]

Hi Surf, Thanks for the test.

[Dan Fromm]

Um, impossible to evaluate without knowing the magnification at which the shot was taken. On my screen, group 6 element 2 is mush, group 6 element 1 is just there. If shot at 1:10, group 6 element 1 is 64 lp/mm. Surely you can do better.

FWIW, at f/4 a 55/2.8 MicroNikkor AIS should resolve at least 120 lp/mm.

[SURF]

Magnification is close to 1:1 as the sensor is APS-C 22.2 × 14.8 mm, 12.2 effective megapixels, 4,272 × 2,848.

[Dan Fromm]

Oh, my. If at 1:1 and my mental arithmetic is correct, group 6 element 1 is 6.4 lp/mm. Oh, my. I hope I've made a mistake. I hope that something in the chain between sensor and my monitor has betrayed you.

[SURF]

Let's talk about long side of the shot. At the camera it is sensor length and it is 22 mm. I have measured the the size at the USAF target that was shot to file - it is 24 mm on the glass target. So we have 22:24 that is very close to 1:1. The crop is 400% enlarged for better viewing.

Bottom line: one can use the setup for DSLR highres scanning with resolution about 3200-3600 dpi on target (put film there instead). You see 3200 dpi, I see 3600 dpi - it's normal when two persons examine the USAF target scan. What's good about all that is that the resolution can be measured.

I have no idea yet what numbers will be be when I will take a better camera and a better lens. Perhaps two times better? Who knows.