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Archive 2017 · Sony A7 with manual lenses light bar on some images

  
 
sharkowill
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p.1 #1 · p.1 #1 · Sony A7 with manual lenses light bar on some images


Hello, I am using a first-generation Sony A7 with some adapted manual focus OM and M42 lenses with a cheaper K&F concept adapters and have noticed overexposed streaks of light along the bottom of the frame of varying size and severity. The effect seems reduced when stopping down and also when shooting in lower light scenarios or in varying angles to strong light sources. I have tried different shutter speeds and turning on and off the electronic first curtain with no consistent ability to remove the issue entirely. I am trying to figure out whether this is due to a light leak with the adapter, reflections off the sensor, or any other possible mechanical issue that I am not thinking of. Has anyone experienced any issues like this, or know of any solutions? I am wondering if a Rayqual, Novoflex, or Metabones adapter would mitigate or eliminate the issue.

Link to samples if issue:

http://www.evanwill.ca/blog/overexposed-streaks-bottom-of-frame-sony-a7-with-manual-lenses



Jul 27, 2017 at 12:40 AM
freaklikeme
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p.1 #2 · p.1 #2 · Sony A7 with manual lenses light bar on some images


That looks like a shutter issue, be it mechanical or a problem with electronic first curtain. Are you shooting with EFCS on or off?


Jul 27, 2017 at 12:49 AM
dumplinknet
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p.1 #3 · p.1 #3 · Sony A7 with manual lenses light bar on some images


It looks like EFCS was left ON when shooting at a fast shutter speed. Usually tho, it is black. I'm not sure why it's white on your A7.


Jul 27, 2017 at 12:59 AM
sharkowill
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p.1 #4 · p.1 #4 · Sony A7 with manual lenses light bar on some images


Thanks for the quick reply! These shots were taken with the EFCS on, but I still notice the issue when both curtains are mechanical, although it appears less noticeable. This is not present for all shots though. It seems as though it is more problematic with bright scenes, so I thought it might be an issue with shutter speed, and I had read on a forum that EFCS was best used for shutter speeds below 1/500 or so. I did some tests but still noticed the issue with varying shutter speeds. The issue is not present in all shots, but as I mentioned seems more noticable in brighter scenes.


Jul 27, 2017 at 01:00 AM
sharkowill
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p.1 #5 · p.1 #5 · Sony A7 with manual lenses light bar on some images


Yes, that is correct. EFCS was on for these shots and shutter speed was 1/400.


Jul 27, 2017 at 01:01 AM
Phillip Reeve
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p.1 #6 · p.1 #6 · Sony A7 with manual lenses light bar on some images


Looks like a camera issue to me but not the typical electronic shutter shading.

Do you have lenses/adapters where the issue does not appear?



Jul 27, 2017 at 01:35 AM
sharkowill
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p.1 #7 · p.1 #7 · Sony A7 with manual lenses light bar on some images


Thanks for the response, Phillip, big fan of your site. The issue appears only with adapters and manual focus lenses (M42, OM) K&F Concept adapters. It does not appear with native E-mount lenses, so through component isolation, it seems to be related to the adapters. I think I will try to get my hands on a Novoflex or Rayqual adapter to see if the issue persists.


Jul 27, 2017 at 01:47 AM
Phillip Reeve
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p.1 #8 · p.1 #8 · Sony A7 with manual lenses light bar on some images




sharkowill wrote:
Thanks for the response, Phillip, big fan of your site. The issue appears only with adapters and manual focus lenses (M42, OM) K&F Concept adapters. It does not appear with native E-mount lenses, so through component isolation, it seems to be related to the adapters. I think I will try to get my hands on a Novoflex or Rayqual adapter to see if the issue persists.

Really curious issue but if it does not appear with native lenses that is strong evidence that it is an adapter issue and I was wrong.

I find it curious that is is really localized. Trying another adapter brand seems like a logical next step. Please update us on your findings .



Jul 27, 2017 at 04:50 AM
mcbroomf
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p.1 #9 · p.1 #9 · Sony A7 with manual lenses light bar on some images


It doesn't look like a conventional light leak, but to isolate it I would wrap some light blocking material around the adapter/lens connection and take some photos, then do the same for the adapter/body connection, and finally over the pin or lever that releases the lens.


Jul 27, 2017 at 05:21 AM
mcbroomf
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p.1 #10 · p.1 #10 · Sony A7 with manual lenses light bar on some images


The other evidence that it's not a light leak is the lower right image on your blog. The dark area from the mans trousers appears shifted to the left, or there is some really bizarre internal reflection that is superimposing a slit of the image shifted to one side. Suggests it might be a sensor read issue, but not sure why only on adapters.

Has this always happened or did it start recently?
Happens on more than one adapter right? (you are using OM and M42 lenses)

Can you put a body cap on the adapter(s) and take a manual exposure at different lengths in dim and bright conditions?



Jul 27, 2017 at 05:52 AM
sharkowill
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p.1 #11 · p.1 #11 · Sony A7 with manual lenses light bar on some images


Hi mcbroomf, thanks for your thoughts. I agree that the perceived shifts are quite bizarre and seem to have differing degrees of offset. This is present on many images, but on my blog, the middle picture of the man's lanyard demonstrates the horizontal shift as well, although in this case it is to the left rather than to the right as is the case with the man's trousers in the street scene.

The direction of the shift changes, the intensity of the light changes, as does the vertical height of the affected area. It has not always happened with the camera, and I have only experienced it now that I bought the adapters to fit my old lenses (this is the first time I have used non-native lenses on the body). The issue is still not present with native lenses, which is very curious. I am experiencing the issue on both the OM and M42 adapters with multiple lenses.

I will try to check for light leaks with the body cap when I get back into the office. I am also going to visit friends and family in Canada in a couple weeks. I have friends with various models of A7 and multiple adapters and lenses, so I can do a more thorough test with different variables then. I will report back once I have isolated the precise problem. Thanks for everyone's prompt and well-considered thoughts and advice.



Jul 27, 2017 at 06:52 AM
sharkowill
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p.1 #12 · p.1 #12 · Sony A7 with manual lenses light bar on some images


To update everyone on the issue, the mystery has been solved. The culprit is the shutter. The problem has progressively gotten worse and is now clearly visible with both native and adapted lenses in certain shooting conditions. The problem seems more pronounced at faster shutter speeds. Going back through older photos taken with this camera, with all lenses there were very subtle signs of the issue that were unnoticed upon the first inspection, but now that I am looking for the problem can easily identify it. I still don't know why the issues seemed to be more apparent with adapted lenses, but at least now know what the cause of the problem was, which is a real shame because the shutter still has less than 20,000 actuations.Thank you to everyone for their advice and input.


Oct 21, 2017 at 06:12 PM





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