scanning with dslr? part II

[boris]

because of the complexity of the project i would like to split it in a few part and try to solve them step by step with the help of the forum.
first question RESOLUTION
i would suggest to start with a comparison of a 1 small piece of a negativ and leave all the other problems aside.
do somebody have a dlsr with a good macro lens AND a drumm-scan of the same negativ? i would ask this membre to make a picture with the dslr of a sharp fraction of the negativ (30x20mm and 60x40mm) and than compare the resolution with the drum scan.
if this first question is clear we could proceed to solve the others.
boris

[Nathan Potter]

Boris, I think a test is almost academic. With most any Dslr all you need is adequate magnification with a good macro lens to see all the detail available in a section of film. One of the issues is that the higher the magnification the smaller the field of view of the film so the greater the number of scans required. The optical resolution, at high enough magnification, will pretty much beat any existing scanner.

Think about the limit of optical microscopy. You'll resolve detail down to roughly a wavelength of light (say 0.5 um). Of course the field of view at such magnification will be small.

For your example above, say close to a full frame Dslr, (say 20 Mp) the pixel pitch is in the vicinity of 7 um. But to adequately sample a transparency you'd want to sample at least twice that pitch, say 3um at the transparency. So it sounds like the magnification is about 2X using a good macro lens. So field of view referenced to the transparency would be half of your sensor size or 15 X 10 mm. All rough estimates.
This kind of resolution would be equal to a good top of the line Aztek scanner. The dynamic range is another matter since the dynamic range of the photomultipliers one finds in high end drums are quite spectacular. Also one must remember that flatness of field and focus at wide copying apertures for the Dslr approach are pretty critical.
But the mechanical issues are solvable problems.

The example above assumes that the detail to be recovered from the film is on the order of the pixel pitch of the sensor, so is an extreme example. The reality of 4X5 film, for example is that seldom does one achieve distinct detail of less than say 20 um (25 lp/mm) so that a magnification factor of say 1:1 would usually be adequate.

Cheers :) :)

Nate Potter Austin TX.

[Ben Syverson]

Depending on the camera, I don't think you even need 1:1... The 5D Mark II has a resolution of about 4000 DPI on the sensor, so a 1:1 photo of 4x5 would correspond to a 4000 DPI scan.

You could get away with half that (2000 DPI or 0.5:1), which is my goal. That way you only need 3 x 3 images to capture the 4x5.

[VictoriaPerelet]

do somebody have a dlsr with a good macro lens AND a drumm-scan of the same negativ?

I updated older page that had comparison between Drum & Flatbed - Added DSLR Macro of same negative:

http://victoriasphoto.com/Notes/Drum_Flatbed/

[sanking]

Victoria,

Thanks for posting. From here it looks to me that DSLR Macro is better than the flatbed, but the big difference in contrast makes the comparison difficult to evaluate.

Sandy King


I updated older page that had comparison between Drum & Flatbed - Added DSLR Macro of same negative:

http://victoriasphoto.com/Notes/Drum_Flatbed/

[Nathan Potter]

Victoria, many thanks for the 1:1 macro comparison. About what I might expect given the many variables involved. The flattening of the sensitometric curve seems reasonable with the 1:1 macro and dominates the other effect of copying which is that of increased gamma. But there are additional opposing variables at play here (scattering from the backlighting technique, possible light scattering from stray front lighting etc.).:) :)

Boris this should give you some early hints of what is possible and suggests that the technique is not crazy. :rolleyes: :rolleyes:

Nate Potter, Austin TX.

[VictoriaPerelet]

Sandy, Nate. CCD flatbeds tend cut contrast severely because of very small CCD, lens & mirror system. CCD scanners with large optics aka Imacon are pretty much "DSLR" systems with line scanning CCD. PMT drum scanners have inherently wide Dmax with rather strong cut off on both sides - makes problem with C41.

PS. I used studio flash to light negative. Light table gives bad color cast (no good for E6 or C41), it can be adjusted with DSLR white balance but that will stretch effectiveness of camera sensor ....

[boris]

thank you victoria!
the exampel is quite impressiv. i would like to direct the attention on the aperture used in the comparison.
the original negativ was made with f: 64 and the dlsr shot was made with f:20 at 1:1 . this would equal a f stop of 40! at infinity. f 64 is alredy pretty small for the 8x10 inch format, but f 40 for a 15x22mm sensor is a real resolution killer.
if we presume a lf negativ shot with f 16 and the dlsr shot made with f 4 at 1:1 resolution SHOULD be much higher.

guys, i have to admitt that i know how to carry my 40 pound linhof gear on a bike :p
BUT have no clue of dslr, scanning technics, software and so on.;)
i will need some help to continue this thread to go on because of the lack of knowledge and language...:mad:
having said this i think that drum scan resolution is possible with ideal f-stop and appropriate technique. ( a volunteer to prove this assumption would be much appreciated.)
how to manage the weak contrast?

[Darin Boville]

Hey Victoria,

Cool tests.

I took the drum scan image and the DSLR image and did a simple levels/apply s-curve in photoshop.

The Drum has better tonality in this simple processing but it has a weird grain--it looks artificial in many parts of the image. Doesn't look like film grain. In addition the drum scan is noticeably blurry in the top half--the DSLR has much more detail.

I'm not criticizing just pointing out the differences--I think I prefer the DSLR version of the three.

Very interesting.

--Darin

[Ben Syverson]

I did some tests today too... I think the aperture you want to be at is more like f/8 or f/11... By f/20, you're quite diffraction limited (especially on a crop sensor).

[Martin Miksch]

IMO this idea alltogether is at least questionable.
You want 24x36 prints from 5x7; lets say print resolution is 300dpi, so you need a scan with about 1400dpi, which all the better flatbeds can do.
Advantage of the scan is -beside the handling- tonal range, which is much better than with a DSLR and you dont use a Bayer-filter.
Regards
Martin

[Ben Syverson]

But if you want a 30 x 40 print of a 4x5, you need 2400 DPI, which no consumer flatbed really resolves.

You don't have to worry about the Bayer filter if you use measured lp/mm (reality) instead of pixel dimensions (fantasy) to do your calculations. In other words, if 4x5 is 125 x 100mm, and we assume it resolves 40 lp/mm, that gives us 5000 x 4000 line pairs we need to reproduce.

• A 5D Mark II resolves about 2062 x 1375 line pairs according to DPReview. 5000 / 2062 = 2.4248. That's how many 5D frames we need horizontally. With overlap, we can shoot 3 horizontally.
• 125mm / 2.4248 = 51.55mm, which is width of the 4x5 that each 5D frame will cover.
• 36mm / 51.55 = 0.698, which is the magnification we'll be using (basically 0.7:1)
• 4000 px (4x5) / 1375 px (5D) = 2.9. Too close to 3, so we'll use 4 images vertically, giving us plenty of overlap.

So, 3x4 images on the 5D should get us all the meaningful information from a 40 lp/mm 4x5. It won't image the grain, but you could, by increasing the magnification ratio, probably just past 1:1. In my mind, getting all the information with none of the grain is preferable anyway.

[Ron Marshall]

I've never looked at the DP Review numbers for DSLR resolution, so I was surprised they are so low; only 57 lp/mm for the D5-II.

I don't own a DSLR, but I have read many posts where people state they are happy with 20x30 prints from DSLR files. But a 20x enlargement would have less than 3 lp/mm on the print. Even considering the higher percieved image quality resulting from digital having less noise, I am surprised.

Is there something I am missing here?



But if you want a 30 x 40 print of a 4x5, you need 2400 DPI, which no consumer flatbed really resolves.

You don't have to worry about the Bayer filter if you use measured lp/mm (reality) instead of pixel dimensions (fantasy) to do your calculations. In other words, if 4x5 is 125 x 100mm, and we assume it resolves 40 lp/mm, that gives us 5000 x 4000 line pairs we need to reproduce.

• A 5D Mark II resolves about 2062 x 1375 line pairs according to DPReview. 5000 / 2062 = 2.4248. That's how many 5D frames we need horizontally. With overlap, we can shoot 3 horizontally.
• 125mm / 2.4248 = 51.55mm, which is width of the 4x5 that each 5D frame will cover.
• 36mm / 51.55 = 0.698, which is the magnification we'll be using (basically 0.7:1)
• 4000 px (4x5) / 1375 px (5D) = 2.9. Too close to 3, so we'll use 4 images vertically, giving us plenty of overlap.

So, 3x4 images on the 5D should get us all the meaningful information from a 40 lp/mm 4x5. It won't image the grain, but you could, by increasing the magnification ratio, probably just past 1:1. In my mind, getting all the information with none of the grain is preferable anyway.

[Ben Syverson]

Is there something I am missing here?
Nope, it's true. DSLRs sort of just suck for big enlargements.

[sanking]

Ron,

No, you are not missing anything. This is one of the little nasty secrets of DSLRs. One can only make a print of 20X30" from a 12-15 mp camera that has adequate sharpness by interpolation. Problem is, interpolation does not create detail, it only expands existing detail. When you get up to 22-24 mp DSLRs you can go up to about 18X24" with real resolution of about 5 lines/mm.

For some subjects you can get away with interpolation. Other subjects that depend on detail are not as forgiving.

Course, if the print does not look sharp you can always step back a few feet!!

BTW, the resolution you note is for 12mp cameras like the Canon 5D. The resolution of the 22mp 5D II and the 15mp 50D is quite a bit higher.

Sandy



I've never looked at the DP Review numbers for DSLR resolution, so I was surprised they are so low; only 57 lp/mm for the D5-II.

I don't own a DSLR, but I have read many posts where people state they are happy with 20x30 prints from DSLR files. But a 20x enlargement would have less than 3 lp/mm on the print. Even considering the higher percieved image quality resulting from digital having less noise, I am surprised.

Is there something I am missing here?

[Ron Marshall]

BTW, the resolution you note is for 12mp cameras like the Canon 5D. The resolution of the 22mp 5D II and the 15mp 50D is quite a bit higher.

Sandy

Thanks Sandy.

That was the resolution DP Review stated for the 5D-II. Which is what surprised me so much. If it had been a 12 MP camera I would not have been surprised.

All of the current 21-24 MP cameras are in that general range.

The DP review resolution for the original 5D is 40 lp/mm.

[sanking]

Ron,

I tested the original Canon 5D with a fairly good L lens and got about 52-54 line/mm with the USAF 1950 resolution target. I did not think that bad since the theoretical maximum of the 5D is about 60 lines/mm. In theory the Canon 5D II should have much higher resolution.

So far have not had a 5D II in my hands.

Sandy



Thanks Sandy.

That was the resolution DP Review stated for the 5D-II. Which is what surprised me so much. If it had been a 12 MP camera I would not have been surprised.

All of the current 21-24 MP cameras are in that general range.

The DP review for the original 5D is 40 lp/mm.

[Ron Marshall]

Ron,

I tested the original Canon 5D with a fairly good L lens and got about 52-54 line/mm with the USAF 1950 resolution target. I did not think that bad since the theoretical maximum of the 5D is about 60 lines/mm. In theory the Canon 5D II should have much higher resolution.

So far have not had a 5D II in my hands.

Sandy

DP Review use a different, more conservative, but not necessarily more accurate method.

But even assuming 54 lp/mm for the original D5, (and by extension 70 lp/mm for the mark II) I am still amazed that people are so satisfied with larger prints having resolutions in the range of 3 lp/mm.

[sanking]

Ron,

Any decent sharpness in prints over about 12X18" (12-15mp DSLR) or 18X24" (22-24mp DSLR) is thanks to the the God of Interpolation and and Genuine Fractals.

Sandy






DP Review use a different, more conservative, but not necessarily more accurate method.

But even assuming 54 lp/mm for the original D5, (and by extension 70 lp/mm for the mark II) I am still amazed that people are so satisfied with larger prints having resolutions in the range of 3 lp/mm.

[AJSJones]

DP Review use a different, more conservative, but not necessarily more accurate method.

But even assuming 54 lp/mm for the original D5, (and by extension 70 lp/mm for the mark II) I am still amazed that people are so satisfied with larger prints having resolutions in the range of 3 lp/mm.

I think they have not really seen a good large LF print to know what they are missing :)

Many of those discussions also do not reveal the viewing distance, let alone comparator, so it's not clear what is meant by a "great 20x30 print".

[sanking]

For the record, I always base my assumption on a viewing distance of about 10-12".

If you make the viewing distance greater, the 5 lines/mm rule has no meaning. In my house I have hanging a 36"X120" print of the Yellow Mountain in China made by a friend of mine from a Canon 20D camera. Because of the place where it hangs one can never get closer to the print than about 30-36 inches, at which distance it looks great. Viewed at closer distance the lack of resolution and grain becomes very apparent.

Sandy King


I think they have not really seen a good large LF print to know what they are missing :)

Many of those discussions also do not reveal the viewing distance, let alone comparator, so it's not clear what is meant by a "great 20x30 print".

[Ben Syverson]

Bah. I have the 5D Mark II. DPReview is very accurate in their measurements. 57 lp/mm sounds just about right.

Everyone has their own limits of acceptable prints. My standards are extraordinarily high, so I wouldn't print 5D Mk II prints bigger than 16x20.

[Ben Syverson]

By the way, DPReview states 2700 Lines per Picture Height for the 5D Mark II, which means 1350 line pairs per picture height. (Lines per picture height is based on video resolution, which measures lines, not line pairs) 1350 / 24mm = 56.25 lp/mm, which is where we're getting that number.

[Cesar Barreto]

I've made some crude experiments yesterday, using a 12Mp camera mounted on a repro column and a Sinar P front standart, also mounted vertically, where I adapted a mask from i900 scanner to hold 4x5' chromes and I may say it did work out fine.
It took some time to figure out the proper alignment and the XY movement steps made with Sinar geared knobs, but once it's done things run pretty fast and are reasonably accurate.
I've made 15 shots and after merging I had something like a 85x108cm image at 300dpi or, in other terms, nearly 10.000 x 12.700 pixels. Resolution is far better than the i900 scanner, but I had no previous doubt about that.
On the pro side, I would say it's easier to control RAW data from ACR than with scanner software and 16bit files can make a great difference on b&w images.
But one should take care about some sort of case sensitive moves on ACR wich seems to create differences between adjacent frames and so I'd suggest not to try much enhancements at this stage.
Auto merging can be tricky if those small frames doesn't show much details, like skies or blurry backgrounds for example and they may be manually merged afterward.

As a conclusion, I think the technique deserves some attention mainly because it can be applied with minimal costs compared to a high-end scanner and once the hardware is set up, one can make a bunch of "scans" on a couple of hours.

[Ben Syverson]

I did some tests today with a few different "normal" lenses mounted on extension tubes...

What I've learned is: this doesn't work. You really need a flat-field macro lens.

I have the X/Y rails and a slightly bigger than 8x10 lightbox (which is extremely even), but I need to wait a month or so until I can afford the Sigma 50mm f/2.8 Macro lens. The Sigma seems to rate better than Canon's 50mm f/2.5, and has better magnification.

[AJSJones]

I did some tests today with a few different "normal" lenses mounted on extension tubes...

What I've learned is: this doesn't work. You really need a flat-field macro lens.

I have the X/Y rails and a slightly bigger than 8x10 lightbox (which is extremely even), but I need to wait a month or so until I can afford the Sigma 50mm f/2.8 Macro lens. The Sigma seems to rate better than Canon's 50mm f/2.5, and has better magnification.

Thanks for the update - I sort of thought a good flat-field lens would be required, even with distortion correction available in DPP or DxO etc. (Did you use any such corrections in your experiments so far?) How are the XY rails working out - good value at ~$50? Could you put a camera on and feel "safe" - I am interested a bit for possible use with shift lenses to correct for parallax in the vertical direction.

Encouraging to hear about the uniformity of your light box.

[Peter De Smidt]

Why not get an enlarging lens and adapt it? Even outstanding ones are super cheap. Get one of the 6 element ones, a Fuji EX, a Rodagon, or a Componon-S.

[Ben Syverson]

Peter, interesting... Wouldn't it be just as expensive to custom-mount the enlarging lens, though?

AJSJones, the XY rails are very good. I would certainly feel safe putting a camera on it, maybe up to 5 lbs or so. There are also little screws to lock down the rails when you get them into position. I'll be using the rails to move the lightbox, not the camera, so I glued a little tripod mount to the bottom of the lightbox. I think it's going to work pretty well.

[Peter De Smidt]

Custom mounting the enlarging lens? Sure, if you have Steve Grimes's shop do it. But there are a number of bellows units out there that take 39mm leica thread, and they too are probably pretty cheap. I used to have a chromapro slide duplicator. The bellows came off and could be easily used for this. I think it was just a standard Novaflex macro rail. Depending on what type of large format cameras you have, that could be another easy way to do it. For example, if you have a Sinar, get two lensboards. Put a t-mount adapter on one of the them, and replace your camera back with it. That'll allow you to mount your dslr on your view camera. Then mount the lens on a regular lensboard. You'll probably need bag bellows, and you probably want to use a 75 to 105mm lens.

There are a whole bunch of ways to do this, and it shouldn't be expensive.

[Ben Syverson]

Interesting... I may experiment with that, but I think for now, I'll stick with a conventional macro lens, because the performance is a known quantity.

I want to be sure that I'm getting as much information onto that 5D sensor as humanly possible...

[Cesar Barreto]

Hi, all.
I've been making a lot of scans following the method I detailed above and some new arguments should be made:
1- a flat-field lens is really a must and even then one may find some trouble with fall-off when stitching in PS. Auto-merging will correct some uneven borders, but will fail badly sometimes;
2- don't ask me why, but CR will open differently adjoining frames even when setting are zeroed and kept the same. If someone explain it, I'll be delighted.
3- working with a macro Nikkor 55mm/2.8, I found the best resolution to be at f/5.6 and at near 1:1 magnification one is really short about dof, but it doesn't help a lot to close the lens any further. So alignment is a major issue.
4- although I have one of those XY rails I didn't care to use it because any time one loosen or tighten so to move the rail, it changes position of whatever is sitting above.
5- it's fun and useful when it goes out right.

[Ben Syverson]

Definitely... f/5.6 seems to be the optimal stop for most of the f/2.5-f/2.8 macro lenses. Closing down to even f/8, you start to see the effect of diffraction.

[sanking]

BTW, what are some of the best macro lenses for Canon DSLRs?

Sandy



Definitely... f/5.6 seems to be the optimal stop for most of the f/2.5-f/2.8 macro lenses. Closing down to even f/8, you start to see the effect of diffraction.

[Ben Syverson]

If your backlight is a fluorescent, then you need to use a shutter speed that's twice as long -- and divisible by -- the rate of your AC power.

So in the US, our power is 60hz. The fastest shutter speed you would use is 1/30th. But 1/30th is not optimal, because you only allow the fluorescents to fire twice during the exposure. I think 1/15 is probably safer.

If you use something faster than 1/30, or a speed that's not divisible by the rate of the AC, you'll get color shifts from frame to frame.



2- don't ask me why, but CR will open differently adjoining frames even when setting are zeroed and kept the same. If someone explain it, I'll be delighted.

[Ben Syverson]

Both the Canon 50mm f/2.5 and the Sigma 50mm f/2.8 rate exceedingly well in all the tests I've seen.

However, the Canon can only go to 1:2 magnification, whereas the Sigma can go all the way to 1:1. The Sigma is also a newer lens design (the Canon was released in 1987 -- it was one of the first EF lenses). Based on these two factors, I decided on the Sigma...


BTW, what are some of the best macro lenses for Canon DSLRs?

Sandy

[Peter De Smidt]

I don't mean to beat a dead horse, but check out Helen B's post here:
http://www.thephotoforum.com/forum/photography-equipment-products-news-reviews/98951-extreme-closups-cheap-nikon-d40x.html

My guess is that the best lens for this purpose would be a Rodenstock apo-Rodagon D 75mm F/4 copy lens, or a comparable lens from the other major manufacturers. These originally very expensive lenses were designed for 1:1 copying of 35mm slides, a purpose very close to the one being discussed here. Regular macro lenses aren't optimized for use at 1:1, and there are a whole bunch of other design criteria, such as autofocus, the ability to perform well at infinity...that the designers of the copy lens didn't need to deal with.

[Cesar Barreto]

Well, actually I hadn't considered variables on light frequency, but I'm using longer exposures, tipically under 1/10th, so I think problems may come from another source.
Those differences on CR rendering seem to be associated with low and high densities areas, but with few features or contrast.
Some odd effects of obscure demosaic routines, I guess.

[sanking]

Peter,

Thanks for the re: to Helen B's post.

Thing is, I already have an extra 75mm f/4 Rodenstock Apo-Rodagon hanging on a spare parts Leafscan 45.

However, if I were to use this lens with a bellows I would have to pre-set it at a given aperture, right? I think this would be fine for scanning with a DSLR, but in fact I was asking about the best macro for Canon DSLR not for scanning but for normal type macro work.

Sandy





I don't mean to beat a dead horse, but check out Helen B's post here:
http://www.thephotoforum.com/forum/photography-equipment-products-news-reviews/98951-extreme-closups-cheap-nikon-d40x.html

My guess is that the best lens for this purpose would be a Rodenstock apo-Rodagon D 75mm F/4 copy lens, or a comparable lens from the other major manufacturers. These originally very expensive lenses were designed for 1:1 copying of 35mm slides, a purpose very close to the one being discussed here. Regular macro lenses aren't optimized for use at 1:1, and there are a whole bunch of other design criteria, such as autofocus, the ability to perform well at infinity...that the designers of the copy lens didn't need to deal with.

[Peter De Smidt]

Peter,
However, if I were to use this lens with a bellows I would have to pre-set it at a given aperture, right? I think this would be fine for scanning with a DSLR, but in fact I was asking about the best macro for Canon DSLR not for scanning but for normal type macro work.
Sandy

Hi Sandy,

Sure, but why is that a problem? I use a Nikon 55mm AI lens with my Nikon D200 regularly. I need to set the aperture on the lens and focus manually, but that's not much of an issue even for non-macro shooting.

[sanking]

I have not done any macro photography in years. Just assumed that auto-focus and auto-exposure would be a big plus for this type of photography. Are you saying it is not?



Sandy





Hi Sandy,

Sure, but why is that a problem? I use a Nikon 55mm AI lens with my Nikon D200 regularly. I need to set the aperture on the lens and focus manually, but that's not much of an issue even for non-macro shooting.

[Ben Syverson]

The bellows and copy lens idea is good, but the rig I'm setting up already has too many moving parts, so if I can eliminate bellows, that's one less variable.

I'm also interested to try a macro for general purpose photography as well... I'm curious to see if it will get me closer to the overall "feel" of a copy lens on a LF.

[Peter De Smidt]

I have not done any macro photography in years. Just assumed that auto-focus and auto-exposure would be a big plus for this type of photography. Are you saying it is not?



Sandy

Right. I'm saying it's not. Even if I use an autofocus macro lens, I turn the autofocus off and use manual exposure. The focus point rarely falls on one of the sensors anyway. My camera is set up such that one button push shows a part of the image at 100% on the lcd screen, which is great for checking focus, and looking at a RGB histogram is a really good way to set exposure. If you don't like manual, use aperture priority with exposure compensation to set exposure.

[VictoriaPerelet]

haven't read this thread for awhile, here are few comments:

1. One can not use regular Sinar P/P2 standard with 1:1 macro lens - shift and raise is limited to 8cm. One can use it with 1:2 lens with loss of detail.

2. Using fluorescent lightbox with color films (C41 or E6) is probably not good idea:). fluorescent has non linear spectrum and can not be corrected with linear filtering (aka white balance). Photoshop correction curve for fluorescent will look very zigzagish

If you can afford (or already have) studio flash unit - best light source. Flash light sources are not used in consumer products (even mid range "pro") cause price but are very common in high end movie production units.

3. Using auto focus (& auto exposure) - almost sure way to get inconsistent results

PS. I'm sure this approach is covered by several patents - commercial/mass implementations may face problems

[Ben Syverson]

Victoria,

From my testing, it seems like the fluorescent source is going to be fine. I get that it's not broad spectrum, but all those spikes do add up to a vaguely white light. I've had good luck with the white balance...

And obviously auto focus and auto exposure is not on the menu... I would never think of making my life that difficult!

[Cesar Barreto]

Hi, Victoria.

It's funny, but my camera shifts 9,5cm. Is there such a difference beetwen newer or older Sinar P models?

[AJSJones]

Peter, interesting... Wouldn't it be just as expensive to custom-mount the enlarging lens, though?

AJSJones, the XY rails are very good. I would certainly feel safe putting a camera on it, maybe up to 5 lbs or so. There are also little screws to lock down the rails when you get them into position. I'll be using the rails to move the lightbox, not the camera, so I glued a little tripod mount to the bottom of the lightbox. I think it's going to work pretty well.

Thanks Ben - I was assuming you would put the light source on the XY and move it (and the film) around under the camera on its stand. That's how I would be doing it. The use with a camera was a possible additional reason the "blow" $50 if it helps with acquiring panoramas with the DSLR to avoid parallax. I think I'll order me a set :)

Cesar, if you have light fall-off from the lens, you can eliminate it either directly in processing the files through newer versions of PS or by making an exposure with no film and using it as a filter mask to even out the illumination (a post-facto centre filter). You'd need to set up an action to process all the images before stitching them. The same applies to any distortion that the lens might generate. Similarly, you should be able to process the raw files to the same WB by synchronizing the settings in your raw converter - if that doesn't work, I'd suspect the light source issue.

Certainly the exposure would be set manually based on the whole image requirements (exposing to the right as much as possible if there are critical shadows) and be the same for each of the images to be stitched. Focus should be a set and forget if the film can be held flat (I would be using LiveView10x view which is really precise).

I'll report back as (and when) I make any progress :)

[SURF]

Nothing to write here about? ;)

Heh. Nearly two years had passed. Any results?

[SURF]

I updated older page that had comparison between Drum & Flatbed - Added DSLR Macro of same negative:

http://victoriasphoto.com/Notes/Drum_Flatbed/

Nice page Victoria. I can see clearly that used flatbed was terrible.

[Professional]

What about using digital medium format instead of 35mm DSLR such as Canon/Nikon?
I have a macro lens for a digital MF, and i hope this can give better and higher quality than just normal smaller formats DSLRs, what do you think?

[Jim Michael]

Look into gigapan micro/macrophotography. There is equipment available for handling the movement of the stage through the field of view, exposure, and software for stitching. I have some questions re the stitching algorithm and how adjacent scans might be assembled, as well as the range of the stage movements.

[VictoriaPerelet]

Nothing to write here about? ;)

Heh. Nearly two years had passed. Any results?

There was part III of this discussion:

http://www.largeformatphotography.info/forum/showthread.php?t=48057&page=1&highlight=Part+iii

Huge increase in quantiy of gigapixels, but not quality:) to get to extreme one can place phase one scanning back in plce of dslr....