Problem with heavy Vignetting

Hi everyone,

I’m kinda frustrated since the results I get are ranging from brilliant to super bad. I can’t quite figure out what’s the problem. But I’m sure it’s my fault since all your pictures come out so good!!

Also - NLP is the best!

First some Examples:




^That’s the photo I’m the most unhappy about - because I actually like it. The vignetting is so uneven that I can’t get any better results than that… :frowning:


^The blue tint on the left.


^It’s subtle here but still there on the bottom.
And at the same time:


^Much better in a Photo taken literally minutes later in the same light.

Most frustrating is the fact that it doesn’t seem so bad at all from time to time:

As I move further away from the negative it seems to get better, but then I get super bad flares:

My scanning setup:
-Sony A7M2
-Canon FD 100 F4 Macro with FD50 extension-ring to reach 1:1 magnification (that’s actually a ultra sharp lens)
-Dörr LT-2020 lighttable (with black tape for no illumination except for the negative)
-Manfrotto Befree GT XPro

My settings are:
-lighttable max power
-stopped down to F16 for less vignetting and sharper images ( :joy: )
-ISO 100
-1/5th of a second shutter speed
-I scan mostly at night with no lights on except the light table!



I hope someone can identify my fault!

Greetz

Felix

Is there any issue when you take an image without film, just the light source alone? I had a case wherelighting seemed to be even but was not. Taking just the light and adjusting the resulting image to the extreme was revealing!

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The earlier Sony A7 models do seem to have some “sensor flare” issues… Because it is mirrorless, the sensor is very close to the lens, and seems to cause more flare in extreme circumstances. As I understand it, the newer Sony models have improved this.

I’m not as familiar with the Dörr LT-2020 as some other models, but I may try going for less power on it, and see it that lowers the amount of flare?

Have you tried WITHOUT the extension ring? Worth a shot… I’ve seen cases where the extension ring cased some issues with flare… also the extension ring may be preventing Lightroom from recognizing the main lens you used, and applying the proper lens correction profile.

Most lenses reach their peak sharpness around F8… so at F16 you will be gaining depth of field, but the lens won’t be as sharp. It’s worth a try to see if F8 makes it better or worse.

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First of all - THX for your replies! :smiley:

@Digitizer
You were right! But the light table itself actually delivers really even lighting.
The actual problem was:
The black electrical tape (I used it to block light around the Area of the single negative) was somehow reflecting the light back down in the light table and back up - resulting in uneven lighting!
Removing some of that around the negative solved that problem.

@nate
I tried it without the extension ring and - as mentioned above - with less masking of the light coming from the LT.
-> NO flare and FAR less vignetting!


^Thats the photo after fiddling around - works for me! Grey is always an extreme condition…


^Thats the flares I get when using the lens with the FD50 Extension ring. When I’m at the closest focusing distance (at 1:1) they disappear but the edges will lose their sharpness.

I was hoping to get the highest resolution possible with my A7M2 :confused:
So then I’ll save some money to get another setup…or live with those 6MP photos.

For general photography on the other Hand:
This lens is incredibly sharp and there’s almost no vignetting even at F4 - I’ll keep it for sure! :slight_smile:

@nate
Do you have any recommendations which lens I could use?

Thanks a lot!

…often, it is a good move to use an original lens and Sony’s FE 90 mm f/2.8 Macro G OSS looks good on dxomark.com

I run old Micro-Nikkor 60mm F2.8 for example.
But Sony 90mm is also good.
I hahven’t used yet Sony’s 50mm macro, but it’s on plans :slight_smile:

Well I‘ll borrow both the 90mm and the 50mm original Sony FE lenses and test them.
The 90mm is really expensive, tho…
The 50mm is said to have quite heavy vignetting too, but thats better than the 1:2 max magnification, I think…I like grain! :smiley:

Please share later your results/findings :slight_smile:

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Are you are talking about the four brownish, bullet-shaped areas in the corners?

Look inside the extension rings from the back (camera) side. Can you see four of anything shiny - screw heads, maybe? If so, you might try to paint the shiny bits with flat black paint.

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You asked what lens? I’ve tried many, on Sony A7 and A6000. Here are some that I like a lot:

  • 90 f/2.8 Sony Macro
  • 70 f/2.8 Sigma Macro ART (half the price of above, AF, goes to 1x)
  • 55 f/2.8 Micro Nikkor AI (manual focus; needs PK-13 tube for 1x)
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You could also use a medium format lens and reverse mount it to your camera. This should remove vignetting - at least the one caused by the lens.

I am using the Sigma 70mm Macro, based on Richards recommendation, it’s very sharp.
To get rid of vignetting, you can use Lightrooms Flat Field Correction plugin.