Inexplicable lights circles, weird lights issues with a perfect setup?

Hello everyone ! :wave:

Here’s my problem…

I’m scanning my films with my camera and I started noticing few problems, even more visible when my films are underexposed like in my last roll.
Here an example, shot on 120mm Portra 160.

You can see tons of little lights circles, and even worse there’s the “shadow” of the lens in the middle

> My equipment :

  • Negative Supply Basic 4x5 95 CRI Light Source
  • Negative Supply Basic 120mm Carrier
  • Sony A7S III
  • Sony 90mm F 2.8 G OSS Macro Lens + lens hood / No lens filter on
  • Bubble level for leveling camera on copy stand

> I close my curtains, I use an homemade construction paper to mask all the light (see photo)
Clearly, there is a problem with light or with my lens.

I tried to scan with an other lens, a Sony 35mm 1.4 and all my lights problems disappear.
But it’s not a satisfying option since the scans are way less sharp than those with my 90mm macro lens.
My question is : does it already happened to someone ? Is my macro lens shitty ? (I’m thinking about changing it for a 105mm Sigma lens) or am I doing something wrong ?

Thanks for your responses !
Have a nice day,
Élise :fairy:
(PS : sorry if I made some vocabulary mistakes, I’m not a native english-speaker)

My cardboard construction :

For me it would be helpful if you could show a picture of your setup with the cardboard light tunnel in place, first with the 90mm and also with the 35mm (or did you even use it then, you would need to have been much closer?). Then if you have a blank unexposed frame of film try photographing that so that you get a mid tone, histogram in the centre as it were. That way the inconsistencies should show up better.


Hmm, you did not tell us what your f-stop is. If by any chance it is f/11 or smaller, the dots you see may be dust on the sensor

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Looks like it indeed.

Are the spots in the same places in all scanned images? If so, the sensor needs cleaning.

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Hello !
Yes it is F/11, but I just checked my sensor and everything looks clean…

Hello !
Okay, I’m going to try to do this ! Thanks for the advice !

Hello Elise, I think that there is a translation problem! Those are pictures of the lens, which is clean for sure but the concern is that the sensor on the camera might have dust on it. Dust on the back of the lens isn’t a good thing but wouldn’t show up directly on your images, dust on the sensor can do though, particularly at small apertures like f11 which you say you are using.

Thanks it would help to diagnose the problerm I think, particularly with the uneven circle in the centre.

…you can check for sensor dust with a (phone) torch and perhaps a magnifier but don’t try and clean it until you have all the right materials to hand, or take it somewhere, the sensor is easily damaged. If there is dust then a blower brush might be all you need, but don’t touch the sensor with it.

Normally sensor spots will be black and slightly out of focus but with colour negative they will appear pale as the image has been inverted.

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Elise, to check for dust on sensor , you point the camera toward evenly lit object - sky, piece of white paper, etc, defocus the lens(!), close aperture down as small as you can ( f16, f22, f32) and shoot. Shutter speed and camera shake does not matter . The dust will appear as sort of dirty spots on otherwise grey background. Any lens will do for the exercise.

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