I have seen some patterns in Raw files and wonder if anyone knows what I’m looking at. I’m not asking for help processing an image but I’m curious how these patterns come about. The technical reason for them appearing. I can’t share the raw of the following file due to privacy concerns for some the people in it.
This is a crop giving enough context to see what the scene contains. I’m shooting wide angle with light hitting the lens so that a flare is produced. (the lens by the way is incredible flare resistant. Pentax HD da 15mm limited) These circumstances produce a maze like pattern on the tree trunk.
So this is what it looks like in Rawtherapee with amaze demosaicing and a curve applied.
Does anyone know what these artefacts are? I’ve seen faint traces of the same pattern when grossly oversharpening pixelshift files. I’ve also heard that Fujifilm X cameras can produce a similar pattern when shot against light. It’s interesting that VNG4 removes the pattern completely.
It looks a bit like the two different greens pattern, you can try to fight using the ‘green equilibration’ adjuster in rt raw preprocessing. But that’s just a wild guess…
Green equiliberation can also be used to equalize green split caused by crosstalk. If you, for example via an adapter, use an analog ultra-wide angle lens with your digital camera the incoming light may arrive at such a low angle that some light passes through one color filter and gets registered in a neighboring pixel belonging to a different color channel - this is crosstalk. As one green channel has blue neighbors and the other red, the first will get crosstalk from blue and the other from red, hence they will separate which can cause mazing
So wide angle lens combined with particular angle of light might cause crosstalk.
