Hi,
I'm building me a DSLR scanning rig, I made some progress, but still have a lot of questions and thought some of you experienced guys could give me some pointers:
What I have today:
For 35mm:
I use dedicated Nikon Coolscan V film scanner - works great.
For medium format and large format I have now assembled the following:
10.5” iPad Pro as light source, placed inside a custom wooden box that’s 3” tall, top of the box has 8.75”x 10.75” x 3mm ANR glass from Focal Point. The glass sits about 3” from the ipad screen so that the iPads pixels are diffused and don’t show up in photos. Above it is Canon 5IV with Zeiss 100/2 MP lens on a stable tripod. The lens has 1:2 magnification, I’m using one 25mm extension tube to get higher magnification, need to get one more to get 1:1 magnification. Black heavy cloth wrapped around the structure to block light. I place film directly on the ANR glass if the film is perfectly flat, if it’s not I put in film holders or tape it.
Have only used it little bit to compare 35mm positive scans to my Nikon Coolscan and so far results are very very good. The major differences I see is that DSLR scans are coming out with more saturated colors, but otherwise looks the same.
Now I’m thinking about what’s next, so here are the questions:
1) How should I go about profiling the camera to get correct scan colors. For positives, should I purchase IT calibration targets? Which ones would you recommend? I see there are targets for slides/positive film, but don’t see anything for color negative – how would I go about that?
2) If I was to change my light source, I’m thinking about:
a. 99CRI non flickering LEDs from https://store.waveformlighting.com/p...=8190565711974
Have you heard anything about these? The specs look great, high CRIs, tightly spaced.
b. What material would you recommend as a diffusion layer above the LEDs. For the iPad all I’m using is clear ANR glass and it works fine as the iPad pixels are very tight. For LEDs, I’m thinking I will need something else below the ANR glass to diffuse the LEDs. I have no idea where to source 8x11 high quality diffusing glass or plastic. Can you recommend something.
c. The LEDs will be significantly brighter than iPad. How should I regulate light output – by exposure in camera or by regulating the LEDs themselves? The LED manufacturer sells non-flickering matching LED dimmer.
d. How closely should I place LED strips next to each other? Should they be literally touching or is it ok to have say 1” spacing.
3) How do you ensure that you lens is perfectly parallel with the film? Should I just print out some square targets and look through the LCD to see if all the lines are perfectly aligned to the edges of the screen or crop marks on the screen?
For now I’m mostly playing with positives, didn’t tackle negatives and understand that will require additional postprocessing to invert and correct colors.
Thank you,
Pavel
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