Vignetting Problem

Hi All,

I’m new to DSLR/Mirrorless Scanning, but after several months of research and setting up I was finally able to scan in about 10 rolls film I’ve had building up. I’m running into a strange issue though - a vignette appears on most of my scanUploading: 7447B4C3-6D6E-4273-91C7-D52965B08020.jpeg… s. In color scans it appears orange, and in BW it appears lighter. At first I thought it was the seals on my FM3a, but I got similar results with shots from my Leica. I tried swapping out light tables, but that had no apparent effect on the vignetting problem (though consequently I found a better solution for color contrast using an iPad and an app over the tracing table I was using).

Here’s my scanning setup: Sony A7riii + Voigtlander 110m F2.5 Apo Lanthar Macro, Negative Supply Film Carrier MK1, Mount MK2 and Copy Stand, light source: I’ve tried 3 but right now I’m just using my iPad and an app that acts as a light table, and finally Negative Lab Pro + Lightroom. Settings are ISO 200, F6.5, in aperture priority. Here are a few examples:

Any advice on the matter is greatly appreciated.

Thanks in advance,

GJ

This looks like the result of stray light leaking in from the sides of your digitizing setup. It may be coming from the clear borders of your negatives, which I notice are visible in the final image, or (more likely) from light entering via the gap between the front of your macro lens and your film holder.

One way to find out for sure would be to try completely shielding the gap between the lens and film holder by constructing a shield out of black paper, draping with dark cloth, etc. You’ll need to do this carefully enough that no light can reach the lens except through the film. Make a few scans this way and you’ll know whether the effect is caused by leaking around the film borders or from the outside.

Hi jlw, thanks for the thoughts.

The motorcycle shot has a borderless guide made by Negative Supply, but all the other shots were scanned using the non borderless guides and have the same problem. Also the light shield you are describing is the same thing as the metal MK2 Mount made by Negative Supply as part of their system. With the 2 photos of the model and the photo of the cat, there appears to be no residual light coming into the lens to cause flare.

Thanks,

GJ

Hi @Groovejunky

Just remember that the vignettes are INVERTED

So here, seeing outer edges being brighter means that the problem in the capture is that your borders are actually too dark - either because they are not getting enough light, or because of lens vignetting from your macro lens.

Some things to try:

  • Try using the MK1 directly on the light table (not on the MK2 mount) - if the film holder is far from the light source, I would expect to see some falloff around the edges similar to what you see in your photos
  • Try setting your aperture to F8.0 to limit the amount of vignetting from the macro lens itself
  • In Lightroom, look at the “lens correction” panel in the develop module, and see if it is finding and applying the right lens correction profile. If not, see if you can find it manually and if applying that helps.

Hope that helps!
-Nate

Hi Nate,
Thanks for the reply. I will experiment with the placement of the film holder without the MK2 mount, I have been using aperture F8 with lens profile correction in lightroom for the last few rolls and I believe that has helped somewhat, though vignette is still present on the edges of some frames.

Resolved (sort of)

I believe I’ve seen decent improvements in vignetting by bringing the light source closer to the film carrier. It’s possible that this is a proprietary issue for third-party light sources when used in tandem with the negative supply MK1 film carrier. I’m ordering one of their light sources and I’ll see if that completely fixed the problem