I am currently testing my new Sigma 180mm f/2.8 macro lens with my 5D 3 and I am having a weird problem. When I take a photo and look at it on the rear screen of the camera, it shows black circular lines at the edges. Depending on the magnification factor of the lens it can be in the corners of the screen (at 1:1.25) or almost a full circle (at 1:1) But if its at 1:30 or something higher there are no lines.
Here is the same thing zoomed in on the camera.
But when I copy the image to computer and open it up in photoshop or lightroom, everything is fine.
It only happens when shooting at 1:1 or close to it, when I take images at 1:10 or something, everything is fine.
When I look through the viewfinder, there are no lines.
When I look through Live View there are no lines.
When I open the RAW on my computer there are no lines.
When I look at the picture on the camera, there are lines.
I've never had this problem with 70-200 II or other lenses but I never had a lens that had 1:1 magnification and this ONLY happens at 1:1 mag or close to it.
It seems like there is some issue with camera's software that creates a preview of the shot, so it can display it very quickly.
Has anyone seen anything like that before? It's really annoying.