Luminous Landscape Forum
Equipment & Techniques => Digital Cameras & Shooting Techniques => Topic started by: pdesmidt on September 18, 2013, 09:04:04 am
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A few of us have been working on DSLR film scanners.
Here's a video of my prototype in action:
http://www.youtube.com/watch?v=gmRHTausFls
The camera is a D600 with a 55mm Micro Nikkor at 1:1 magnification. (Currently, I use a Rodagon D 75mm F4 at 1:1.) The scanner takes 25 pictures to scan a 4x5" piece of film. It is controlled by an Arduino Uno, with two EasyStepper drivers for the stepper motors.
Daniel Moore's more elegant version can be seen here: http://www.youtube.com/redirect?q=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DPXy7RJwIBAo&session_token=bkG0387jpsr60MhwM67c2bpOu2p8MTM3OTU5NTcwOEAxMzc5NTA5MzA4
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That's pretty nice. Much more advanced than I'm going. Currently I have been duping 6x6 with a Nikkor 55mm (pre-AI) and a piece of PVC pipe. Was using a D7000, but switched to a E-M5, haven't tried working with the negatives since the switch. About to adapt an old enlarger to the task (paid $15 for the thing, might as well try).
Can I ask what you are using for the light box? I have a small slide viewer, but it doesn't seem consistent edge to edge.
All of this makes me want a 4x5.....
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Thanks, it's been a lot of work, but it's been fun.
I started with a Portatrace light box, but it was too big and not very even.
Next, I build a Styrofoam lined mixing chamber and used flash. That worked pretty well, although there was some variation from flash to flash.
What I use now was made using RGB LED strips. Being able to control each channel separately is useful. I used the LED strips from Lee Valley: http://www.leevalley.com/US/wood/page.aspx?p=70326&cat=1,43349,70322
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Some more pictures:
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Hi,
Nice project! Thanks for sharing.
Cheers,
Bart
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Very impressed! How are you dealing with focus and keeping the film flat?
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With flat film, the negative mask holds it flat. I've also taped the negative to the glass without problems. If the negatives are squirrelly, I'll wet mount them using Lumina fluid and scanning mylar.
I focus using live view zoomed all the way in. Focus is achieved by moving the whole lens, extension tube, cameras system up and down using a Velmex 4000 series unislide. (At 1:1, that's the best way to focus. At that magnification, changing lens to sensor plane distance changes magnification more than focus.)
So here are some comparisons.
First, we have a scan from the dslr scanner. The layers are from different lenses.
https://dl.dropboxusercontent.com/u/...ergger_200.tif
This is a full-sized 8-bit Gamma 2.2 layered file. The sample area was the center of a 4x5" of Bergger 200 film developed in PMK. It was taped to the glass. With one lens, the exposure was 1/100th of a second, and with the other one it was 1/60th. I used the light source to roughly equalize the channels.
The files were brought into Lightroom 5, where I inverted them. I then used the curve feature to stretch each channel until it almost clipped, which should be pretty representative of actual use. Default Lightroom sharpening was applied to both. (Each could stand quite a bit more sharpening.)
After bringing the files into Photoshop, I converted to Grayscale 2.2 using the green channels, which showed a little more detail.
Second, we have a scan of the same area on my Cezanne:
https://dl.dropboxusercontent.com/u/..._test-0109.tif
I scanned this version at 8000 spi and then down-sampled to roughly the size of the dslr scan in Photoshop using Bicubric sharper. No other sharpening was applied.
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Using a Edmund Scientific USAF hi res test chart gives 3000 dpi real resolution with my D600 and 75mm F4 Rodagon D at 1x magnification. Daniel Moore's D800e with a Schneider 80mm Digitar at 1x gives 3600 dpi.