Can someone tell me what causes this.

I think someone is holding a hoop in front of the lens!

Coat is on.......
 
stupar said:
If I recall correctly peripheral illumination only works with Canon lenses and the way the camera recognises the lens is through a number code. If the Sigma lens has a number code which matches a Canon lens the body will assume its a Canon lens attached and apply the peripheral illumination correction if its active. So it may be this that is the issue.

Alternatively I could be really wide of the mark with both possible cause and technical information so happy to stand corrected. :)
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That sounds very logical but this issue just developed. She had been using this lens and body without any problems until now. That is why it seems as though it is a software malfunction
 
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Have you perchance ever played any pranks on her and this is her revenge? ;)
 
shaylou said:
That sounds very logical but this issue just developed. She had been using this lens and body without any problems until now. That is why it seems as though it is a software malfunction
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Previously with Peripheral Illumination correction disabled?
 
HoppyUK said:
Previously with Peripheral Illumination correction disabled?
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But even with PI, it shouldn't produce an overlay.

At least it doesn't with the 6d.
 
odd jim said:
No FF canon is designed to take an APS-C lens so doubtful!
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Canon EF-S lenses won't fit on a Canon FF body but there are plenty of third-party lenses designed for crop sensors which will physically fit and work on a Canon FF body but with vignetting.
 
Vertigo1 said:
Canon EF-S lenses won't fit on a Canon FF body but there are plenty of third-party lenses designed for crop sensors which will physically fit and work on a Canon FF body but with vignetting.
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Yes true, but this isn't vignetting. The circle is too defined and there's no darkening outside the circle.
 
odd jim said:
Yes true, but this isn't vignetting. The circle is too defined and there's no darkening outside the circle.
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Oh yeah the OP's issue is nothing to do with this scenario I grant you :)
 
odd jim said:
But even with PI, it shouldn't produce an overlay.

At least it doesn't with the 6d.
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odd jim said:
Yes true, but this isn't vignetting. The circle is too defined and there's no darkening outside the circle.
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The peripheral illumination thing is only a guess, though from the evidence, I'd say it's quite a likely one. We don't know details of how PI was enabled in-camera - I don't think Shayne does and maybe not his friend either.

What I think we're seeing is an artefact from the PI not working properly because of a compatibility issue with the lens, and I'd assume it would disappear with PI disabled when the camera would then function entirely normally. If that turns out to be the case, then a firmware update by Sigma should sort the lens.
 
HoppyUK said:
The peripheral illumination thing is only a guess, though from the evidence, I'd say it's quite a likely one. We don't know details of how PI was enabled in-camera - I don't think Shayne does and maybe not his friend either.

What I think we're seeing is an artefact from the PI not working properly because of a compatibility issue with the lens, and I'd assume it would disappear with PI disabled when the camera would then function entirely normally. If that turns out to be the case, then a firmware update by Sigma should sort the lens.
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I did not get the information about when the pi was on. Richard is correct, I don't know this person with the problem and I was just trying to help them out and I thought it was an interesting issue to chat about. I did ask but didn't get a response.
I gave her the info that we gathered here so hopefully it helps resolve her problem.

Thanks everyone.
 
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