Bullseye Artifact on Long Exposures

[ENGTick]

Hi. Newbie hobbyist who started last June. Does anybody know what would cause the "bullseye" in the center of this shot? I shot this using an a7r iii with FE 2.8/24-70 GM lens. My settings were 15 sec, f/4, iso 800. Also, I didn't see the bullseye on shots at 5 sec, f/4, iso 800. I had Long Exposure NR off for both shots. Thanks.

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Edited January 26, 2019 by ENGTick

[VTC]

Odd but taking a wild guess here... Stabilization turned off? It's recommended for tripod use. When shooting with a matte box if I'm not careful shooting towards the sun or have the flag off position I'll get a reflection of the lens on the 2nd surface of the filter but it presents much larger than what's shown here.

[VTC]

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[Chrissie]

In the TO's image, this looks like Newton's rings to me.

Edited January 27, 2019 by Chrissie

[ArnoldLayne]

Allow me to add my own 'bullseye puzzle. I agree the OP photo looks like Newton's rings, now that I know what that is. But my bullseye is much larger. Have you seen this? It's not dependent on lens. a6000

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[dbmiller]

16 hours ago, ArnoldLayne said:

Allow me to add my own 'bullseye puzzle. I agree the OP photo looks like Newton's rings, now that I know what that is. But my bullseye is much larger. Have you seen this? It's not dependent on lens. a6000

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Looks like the lens correction being applied for vignetting. And possibly then pushed in post?

Try turning off "Shading Comp." on the camera. Google that and you'll find a bunch of info.

[txtrigg]

I have the same issue with my A7RIII - I looked at my raw files  out of the camera and they all had this bull's eye. I'll try the same Shading Comp setting. I was also using compressed raw files - I know there have been some issues with compressed raw images and originally thought this was related. I'll have to go see if I can find any of them - I think I trashed them all because the bull's eye was so stark it made them unusable.

 

*edit: added my camera model.  

Edited December 13, 2020 by txtrigg

[Eskimotom]

Looks like a lens reflection (reflected back) on a UV filter or any other glass threaded on the end of the lens.

Edited March 2, 2021 by Eskimotom
clarification

[XKAES]

I agree with Eskimotom.  These look like very mild lens edge reflections onto the camera sensor -- filters would add to this, as long exposure noise would, too.  Take the same picture with a different lens at the same speed.  If it shows up again, but looks larger, smaller, fewer or more rings -- it would suggest mild internal lens reflection.

One possible solution MIGHT be a longer lens shade or a slower shutter speed (to reduce noise -- which I assume was already reduced).

Edited March 5, 2021 by XKAES