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Thread: DSLR Scanner Project: Does it work?

  1. #11

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    Re: DSLR Scanner Project: Does it work?

    I agree about maximum resolution. I don't see any new details at 10.000 dpi (9 to 16 pics on D600) vs 4.000 dpi (1 pic), I made this mostly for experiment. I have only 35mm negatives and I need to try panorama stitching software.

    I use AutoPano Giga Pro, it have plugin to import from Gigapano which works well for my mosaics. It take few minutes to stitch one negative. I also tried Microsoft ICE, it works too, but I prefer AutoPano.

  2. #12
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    Re: DSLR Scanner Project: Does it work?

    one of the downsides of the method: you need a good dslr, and if you count to cost of the dslr, it's a pretty expensive scanner. I do have a D70 lying around somewhere but you would have to stitch for sure with a 2MP camera.
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  3. #13

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    Re: DSLR Scanner Project: Does it work?

    You could get Nikon D3200 for $200-$300 and get more resolution from one negative than D600. 60mm/2,8D for $200-$300.
    I also spent $150-$200 for steppers+electronics+LED strip+plywood+wheels+rails etc. Microsoft ICE is free but AutoPano Giga is 200 euro.

    It is cheaper than Nikon 9000 but still you need to know how to make this work: engineering, programming etc.

  4. #14
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    Re: DSLR Scanner Project: Does it work?

    I didn't realize D3200 were that cheap.

    Doing a whole negative in one shot appeals to me the most.

    Are there any mirrorless cameras that have high resolution, or is it only DSLRs that have top-end sensors?
    Science is what we understand well enough to explain to a computer. Art is everything else we do.
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  5. #15
    Peter De Smidt's Avatar
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    Re: DSLR Scanner Project: Does it work?

    Just for the record, I use a template in PTgui to stitch hi-res files. It works very well. I've also briefly use Autopano Pro for other stitching tasks, and it gave great results. I ended up going with PTGui, as Daniel is very knowledgeable about it. When Microsoft Ice works, it's terrific, and it has a .....I"m forgetting the term....mode for stitching where the camera is moved (instead of pivoted), and that's ideal. But when it doesn't work, it really fails. For small stiches, say 3 frames, I do it simply in Photoshop. Load all three, say, files as layers. Turn the top layer invisible. Select the second one. Turn it's blending mode to "difference". Pick the move tool. Now use the arrow buttons to nudge the file into place.

    Regarding cameras, some of us have to have a digital camera for other purposes. If I was buying a camera just for scanning, I'd buy a cheaper APS camera, as the smaller frame puts less stress on the lens, as the corners are usually what can go a little softer. For big stitches, a camera that can be controlled by an Arduino is helpful. Nikon is no problem. I expect that Canon wouldn't be hard to get to work, but I'm not sure about other brands. If they can be used tethered, you're probably ok. Until recently, Nikon cameras had a bit of an edge in dynamic range.

    Sure there are mirrorless cameras with high resolution. Sony has a bunch.
    "Why can't we all just get along?" President Dale, Mars Attacks

  6. #16
    Peter De Smidt's Avatar
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    Re: DSLR Scanner Project: Does it work?

    For the best quality with a dslr scan, one should maximize the information captured by each of the channels available with a specific capture system. If it's a monochrome sensor, then it's one channel, but if it's an R,G,B sensor, then it applies to all three channels. To do this, you want to Expose To The Right (ETTR), which means to give each channel as much exposure as will almost cause highlight clipping, assuming that no area of the negative should be clipped. This will maximize tonal separation in each channel while minimizing noise. While this is obvious for color film, it also applies to bw negatives, especially if a staining developer is used, although the green channel will be the most important, as most image detail with digital captures depend more on the green channel than on the others, although doing this is not as critical as it is with color images.

    This isn't as easy to accomplish as you might think. In the first place, your camera's histogram and display image are based on a jpg that's made according to your camera settings, and that's the case whether you are shooting in jpg or raw. These jpgs often pump up color and contrast to give a pleasing jpg image, but that's not what we're after here. We want to optimize the capture. So if you're using your camera to determine exposure, go into it's picture control settings, and set the controls for the lowest saturation, contrast, sharpness settings as you can. These only apply to the jpg and histogram. Since you're shooting raw they won't be cooked into the captured file. It's ideal if you can save that as a preset. Doing this will often show that you need to give a stop or more exposure to truly ETTR. Underexposing by a stop is a huge deal when dealing with a slide with a very high density range.

    If you're shooting tethered, then there's also a gotchya to avoid. Make sure to set the raw processor to do as little processing as possible. Namely, set the input profile to "neutral" or "linear". If you use something like Capture One's Auto, it will significantly brighten underexposed images. That's great if you want an underexposed image to look good, but it's better to not have an underexposed image, and you want your raw processor to show you that your image is underexposed if that's the case. This applies not only to scans but to optimizing studio lighting if you're shooting tethered.

    If done properly, these files will appear too bright. The best way to fix this is in raw processing, being very careful not to go too far.

    Another point to emphasize is that no stray light should come out of your light source. The only light visible from your source should be coming through your negative, with as little of the clear base of the film showing as you can. If you don't mask the negative appropriately, you will exacerbate flare, and this will cause obvious artifacts, or, worse, a not immediately obvious loss tonal separation. It would be like traditional printing with a slightly too bright safelight.

    The implications would seem to be that you want a light source that RGB levels are controllable, and that's what Daniel and I did, but that approach does have some practical problems, as it can lead to banding due to the interaction of pulse width modulation and shutter speed. Could that be overcome? Sure, but it's not straight forward. LEDs have come a long way in the years since Daniel and I built our current machines. In particular, there's now a whole breed of high color quality LED lights intended for shooting video. These are likely much higher quality than the RGB strips in our current scanners. Daniel will be testing an affordable Dracast unit over the next couple of months. Hopefully, it'll also allow us to increase the shutter speed to minimize vibration from shutter actuation. These are most likely to occur with shutter speeds from about 1/8th second to 2 seconds.

    Happy Scanning!
    "Why can't we all just get along?" President Dale, Mars Attacks

  7. #17

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    Re: DSLR Scanner Project: Does it work?

    Peter, can you link to your write up about the Arduino control system and the motor drive you're using, as well as to your light source? I've read the several threads that are started here and there on LFPF, but you guys have made a lot of references to "oh, I explained that in the other conversation we were having" without actually providing a direct link to concise enough information to allow someone to replicate what you've done.

  8. #18
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  9. #19
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    Re: DSLR Scanner Project: Does it work?

    I have hqad an Epson 750 for ten or so years. From what I can understand from reading this thread, I will keep it and mot try to do it with any sort of DIY scanner set up.

    I scan 4x5 and 8x10 negs and transparencies with the 750 and it seems to be working for me.

    Thanks to everyone who contributed the good info on this thread.
    Last edited by Drew Bedo; 23-Aug-2017 at 10:37.
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  10. #20
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    Re: DSLR Scanner Project: Does it work?

    The thing is that 4x5 and 8x10 is the easiest thing to scan, so you can get good results from flatbeds, at sufficient resolution, and without grain aliasing, with large sheet film. The capability of flatbeds breaks down for 6x9 and smaller, and what good smaller-format scanners there were, are no longer in production or supported, so there is every reason to be interested in DSLR scanning for smaller formats, at least as much as for larger ones..
    Science is what we understand well enough to explain to a computer. Art is everything else we do.
    --A=B by Petkovšek et. al.

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