Required repeatability increases significantly when multiple images of a negative are taken. The issue is the difficulty of stitching areas without much detail, such as a white wall, blank sky..... A good way around this is to build a template in PTGui, using a negative with good detail everywhere to make the template. If your scans are highly repeatable, then you can simply apply the template to future scans. With Daniel and my systems, this works really well.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
adding a bit of what i know in terms of this stuff. I think the rise of 3D printing will help significantly in terms of manufacturing. Bear in mind a kid in middle school was able to print an entire set of braces for himself (many individual sets of braces) with little to no proper equipment for less than $100. With all the higher end plastics available today that weren't back in the 90s/2000s and more accessible communication in terms of manufacturing. I'm willing to bet with a decent start up lump sum someone with the know how could easily get a modern drum scanner onto the market. whether it be for pros or for the normal person with a few thousand burning a hole in their pocket. yes drum scanners back in the day were expensive, but so were the first computers, nowadays one can walk into walmart and get a half decent machine for $600 thats millions of times more powerful than the $10k beasts from back in the day. why not the same for drum scanners? If anything I'm willing to bet one could take an old howtek 4500 or 8000 and scan all the parts with a 3d printer. print off the parts, keep the moving parts metal for strength, and just update the software and processors to accommodate todays much more capable machines. I have a Macbook air and I've edited 3gb files on it before (granted it was a pain) Im willing to bet it can be done with around $1million TOTAL to get a new scanner on the market for under $5k. at the very least someone will be out a million dollars and there will be a few hundred modern scanners floating around for labs and pros to use.
I should also add there is a fairly small company called creekside digital that uses a phase 1 80MP digital back over what appears to be an enlarger chassis with the camera system attached and the film on a ligthbox below. Honestly its a great idea but for some reason they impose some comparatively small size limits to all formats compared to what one could do with a moderately priced flatbed or cheaper drum scanner. In practice they're quite clever but my only beef is the file limits.
I have made side by side comparisons of scanned images (using Fuji finescan 2750 from 8x10 color transparencies) and a Nikon D800E (stitched shots of the same 8x10). The DSLR images are much better, more resolution, better contrast and richer colors.
After reading this forum I build such a scanner myself. I have no large format negatives (or ever MF) so I test it scanning old 35mm films. I use Nikon D600 and Nikon 60mm/2.8D.
I usually scan negative at 1:1 magnification so I don't need stitching panorama. I get 24 megapixels (4000 dpi) from negative. I also have cheap macrotubes so it possible get 2:1 magnification (maybe more). At maximum magnification I got 120 megapixels (9000 dpi) from one negative (12 D600 frames). I can't see big difference between 120 mpx and 24 in my scan but maybe with better film and camera/lens it's possible to get more quality scanning at higher than 1:1 magnification. I think that 50 mpx per negative will be enough. Here is a video of scanning process.
I have 30x30cm light-table which is moved by two nema17 stepper motors controlled by Arduino.
Good stuff! Thanks for posting. My own experience with my D600 is that there isn't much advantage going above 1x magnification, even with lenses optimized for those magnifications. I did a test with a 35mm image taken with Technical Pan film, shot on a very heavy tripod, using the taking lens's best aperture.... I compared scans done with a 75mm Rodagon D f/4 @ 1x magnification to one done with a Nikon 5x Measuring Microscope lens, and maybe there was a tiny difference. But maybe not. There was a huge difference when I scanned a high resolution test chrome on glass resolution testing plate. So the higher magnification setup did produce more subject detail, if there was such detail on the subject, but at least in my case, my film negatives didn't have useful detail that needed the increased magnification. If there wasn't an obvious difference using TP on 35mm, I doubt very much that there would be any difference with medium or large format negatives. Using different lenses might give a different result. If the lens used at 1x isn't very good, a scan at 2x might out perform it.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
Hi Peter! Any words about geometry and microgeometry? Do you use any profile for that? Have you checked those BTW? What kind of adjustments do you use when you put the camera in place?
That must be a nice machine. Saw it on youtube some years ago.
PS. I have not read all the thread.
PPS. Good thing that you bought USAF target. ;-)
Hi Surf,
By "geometry and mircrogeometery" do you mean size distortions from stitching? If so, I haven't done extensive tests, and my scanner is currently in pieces, and thus it's unlikely to happen soon. By "profile" do you mean a template for stitching? If so, yes, I made a special negative to created a template in ptgui. The scanner is repeatable enough to allow other 4x5 scans to use the same template. Regarding mounting the camera, I use a long Arca quick release plate, 8" I think. The Nikon extension tubes are bolted to it. It mounts to a Velmex 4000 series unislide via an Arca clamp. Once the lens system is mounted, it stays on the Velmex. The Velmex can be moved very precisely to focus. I hope that helps.
a
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
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