"Stair casing" at 100%

Unregistered User · 06-20-2018, 10:36 AM

So I have concluded that it is the Adobe Camera RAW that does this. I have tested several different cameras and the problem comes no matter the camera. Now latest a Canon 5D, the first one.

But no solution...

Gimbal · 06-21-2018, 09:29 AM - **1 Like**

It guess that is an artifact from the demosaic algorithm.
If you have some time to spend there is a lengthy discussion about a similar problem here:
Diagonal interpolation correction artifacts with AMaZE Demosaicing - RawTherapee - discuss.pixls.us

Aberrator · 07-06-2018, 05:13 PM

I think the trouble makers here are highlights when at least one channel has clipped. Different demosaic algorithms or highlight reconstruction methods could help. Careful EV compensation or exp. bracketing when shooting to prevent near clipping.

Years ago, when I was using K10D and some old version of RawTherapee, sometimes weird maze-like patterns would form on near-clipped highlights, that weren't there on jpegs. K10D has only 10M pixels and strong AA filter, so sensor resolution or lack of a filter probably are not affecting this. With Bayer sensors, when one or two channels clip, demosaicing has big gaps of information to fill, producing artifacts. Just my theory.

**jbinpg** · 07-06-2018, 09:41 PM

Does this also happen with pixel shift images where there is no inter-pixel interpretation?

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06-20-2018, 10:36 AM	#46
Unregistered User Guest	So I have concluded that it is the Adobe Camera RAW that does this. I have tested several different cameras and the problem comes no matter the camera. Now latest a Canon 5D, the first one. But no solution...

06-21-2018, 09:29 AM - 1 Like	#47
Gimbal Pentaxian Join Date: Apr 2007 Location: Sweden Posts: 2,106	It guess that is an artifact from the demosaic algorithm. If you have some time to spend there is a lengthy discussion about a similar problem here: Diagonal interpolation correction artifacts with AMaZE Demosaicing - RawTherapee - discuss.pixls.us

07-06-2018, 05:13 PM	#48
Aberrator Forum Member Join Date: Aug 2014 Location: Kaunas Photos: Gallery Posts: 97	I think the trouble makers here are highlights when at least one channel has clipped. Different demosaic algorithms or highlight reconstruction methods could help. Careful EV compensation or exp. bracketing when shooting to prevent near clipping. Years ago, when I was using K10D and some old version of RawTherapee, sometimes weird maze-like patterns would form on near-clipped highlights, that weren't there on jpegs. K10D has only 10M pixels and strong AA filter, so sensor resolution or lack of a filter probably are not affecting this. With Bayer sensors, when one or two channels clip, demosaicing has big gaps of information to fill, producing artifacts. Just my theory.

07-06-2018, 09:41 PM	#49
jbinpg Site Supporter Join Date: Mar 2008 Location: Prince George, BC Photos: Gallery \| Albums Posts: 3,546	Does this also happen with pixel shift images where there is no inter-pixel interpretation?