What's this??!! ( circular ring artifacts )

Started Feb 26, 2014 | Discussions thread
mbietenholz Regular Member • Posts: 101
Re: What's this??!! ( circular ring artifacts )

wictred wrote:

mbietenholz wrote:

On my NEX-6, the lens-corrections do NOT affect the RAW. The lens corrections for the kit lens (vignetting, distortion and chromatic aberration) are pretty obvious, and if I open the file in RAWtherapee, I can turn any of these corrections on or off at will.

Oh but they do.

try the following:

- take a severely underexposed shot in RAW.

- add at least 3 EV in PP (might need up to 5)

try the same with and without vignetting correction.

see if there is a difference.

with lens correction activated, you should see a circular banding effect. the RAW does not have the vignetting correction applied of course, however the circular banding effect is there...

This is the same kind of circular banding that is described in the Ricoh related article linked in the original post.

I just took two examples with the NEX-6, this is how it looks after pushing 5(!) EV in PP

both are shot in RAW, imported into LR, exposure changed by +5 EV, no additional changes.

vignetting correction on

vignetting correction off

This is completely irrelevant in normal usage. The original image is almost pitch black.

I'll try this later when I get a chance.   I don't get it - turning the vignetting correction on in the camera does *not* cause the vignetting correction to be baked into the RAW data, but *does* cause some other subtle change in the RAW data that produces banding at very low light levels?

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