Looking for some advice here. I’m happy with the sharpness and colors that I can get from my cheapo setup, but I can’t seem to fix the vignetting I’m getting. The setup is as follows:
Nikon D3300 (RAW format)
Nikon Micro-Nikkor 40mm F2.8
JJC digitizing adapter directly attached to lens (no extensions or anything)
Replaced LED with Ulanzi VL-81 (CRI95+)
I’ve tried different apertures, exposure compensation, LED brightness, replacing the LED, flat field correction, etc. I just can’t seem to get rid of the constant vignetting I’m getting. On bright daylight shots it’s not as noticeable, but on darker shots it can pretty much ruin the scan. Lens correction with vignette correction does help, but I usually have to have it cranked to 200. Does anyone use this combo that can provide some help? Is it just a limitation of the lens/sensor combo?
Hi there, welcome to the forum. I had a quick look at a review and it looks as if that lens can suffer from vignetting at wider apertures even with the lens profile selected. What aperture are you using? Are you copying colour negatives so that after processing the vignetting shows up as pale corners? Colour negatives are particularly adversely affected by lens vignetting.
You could also try photographing the panel on its own in the dark using the same exposure and at the same distance from the lens but without the film holder just to see if the film holder might be contributing to the problem. A tripod would be handy for that of course but you could probably manage without, it doesn’t have to be critically sharp but it does have to be focused at more or less the point where the film would have been.
I’ve tried apertures from around f4 to f22. There typically isn’t much difference. I’ve settled on f5.6 as it seems to be the best from my testing.
Yes I am copying color negatives and converting with NLP, which is giving me the orange tinted vignette after conversion. The JJC adapter had two slots for the film holder; one closer and one farther away from the lens. I did notice the vignetting would be slightly reduced if I used the farther slot, but not completely eliminated. Since changing LED lights, I can only use the closer slot. The bonus is my “scan” is a decent amount bigger if I want to crop or blow up.
Is it possible the film holder could be the cause of the vignetting? I like this setup because it’s easy to throw on a desk with a small tripod and scan away. I’ve tried other things like only scanning the “matte” side of the negative, completely dark room, etc. Like I said, on bright colorful shots it’s not as noticeable. But on dark shots it’s pretty bad at times.
If THIS is the lens you use, vignetting should be no problem.
I’d try to snap a few pictures without the funnel and diffusor and point the lens towards an evenly lit surface like a white wall. Put as much distance between you and the wall so that the photo you take from it will be unsharp (which comes with close focusing) and show none of the wall’s edges. The wall needn’t be white, but it should be unstructured (a brick wall is less desired). Take a few shots with different camera orientations, and also with moving the camera in a long exposure to blur/average anything that could result in uneven exposure. I usually point the camera upwards towards the ceiling.
Also, the funnel that holds the negative to the lens can reflect light which would lead to darker corners, once the negative has been converted. Last but not least, the negative can be vignetted, which would show as brighter/paler corners as @Harry wrote above.
Does this mean that your 35mm negative is at least almost filling the frame now?
Well it might be a factor here which is why eliminating it to test how you get on without it would be worth trying.
At f5.6 it doesn’t seem that lens vignetting should be a problem and I wouldn’t use much smaller apertures than that as diffraction takes its toll. If you have a clear unexposed piece of colour negative film from either the beginning or end of the roll then you could try that, exposing so that the histogram is centred or thereabouts. Then examine that in Lightroom to see how much the corners differ from the centre in terms of brightness. Flat Field Correction should have dealt with your problem so I don’t know why it didn’t but it is simpler to use the radial filter tool so long as the vignetting effect is indeed radial. Once you have found a setting that eliminates the vignetting you can save that as a preset and run it across all your ‘scanned’ images whilst still in library mode, or even apply it upon import.
If in spite of all trials the vignetting remains one easy solution could be to frame larger than the negative so as to leave the vignetting areas out of the negative itself?