Issue with concentric rings on E-M1 Mark II (edited title)

Started Mar 19, 2017 | Discussions thread
OP Astrotripper Veteran Member • Posts: 5,609
Re: But what could possibly cause this?

Danielvr wrote:

With concentric rings, you'd think the problem is optical, i.e. caused by a lens or filter. But you're seeing it with a wide variety of lenses and I'm sure you didn't put a circular polarisation filter on each.

Yes, that's why initially I thought it was the Leica. But that's not the case. The rings are concentric because that is the gradient of vignetting. I'm pretty sure that if I had a "straight" gradient somewhere in the photo, the same issue would pop up, but with green stripes. Or rather, if that would be the case, then that would eliminate the optical cause. My initial guess was that maybe microlenses for each color had different transmission characteristics depending on angle of light rays coming from the lens. But that sounds like a stretch.

But still, it puzzles me why Panasonic 1.7/20 seems to not be affected. It does exhibit pretty noticeable vignetting, so why no issues?

I've seen 'natural' rings in overprocessed photos of the Moon's halo, and in photos of pulsed laser beams.

Yes, that is often posterization caused by noise reduction.

None of that applies here.

Well, it might if Olympus applies noise reduction separately to each color channel in raw file. Then you end up with posterization that is "out of sync" for each color. No idea if this is the case here. Probably unlikely that they would make such a stupid mistake and not notice it. And the fact that I got one "greenish" image for no apparent reason rather suggests that something is not right with the camera. Maybe some irregularity in signal processing that makes some values larger and some smaller? If that happened, any gradient in the image would be messed up by this, while you would not notice it otherwise on "normal" photos.

But it has got to come from somewhere..

Did you take all these shots with IBIS on? And if so, what happens with it off?

On, off, tripod, handheld, card in different slot. No difference. Does not seem to be as obvious at high ISO, but I'm pretty sure stacking would reveal it, like it did with one of my initial samples.

 Astrotripper's gear list:Astrotripper's gear list
Sigma DP2 Merrill Olympus PEN E-PL1 Olympus OM-D E-M10 Panasonic Lumix DMC-GM5 Olympus E-M1 II +17 more
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