FS7: Prores Color Block Artifacting When Shooting Lunar Images

basspig

basspig

Veteran
I ran across something unexpected when shooting the moon last night.

I'm using a Sigma 150-600mm zoom. I managed to get a pretty good focus on the lunar surface.

I used 2K crop mode and recorded both internally and to the Shogun recorder.

The Shogun was set to Prores HQ.

CINE EI with S-log 3, s-gamut was used.

What I'm seeing in the NLE looks like JPEG block artifacts, but with the blocks having a cyan tint to them. These appear in the darker parts of the moon's surface.

The XAVC footage does not show colors but there are rectangular areas that match up closely with the Prores footage. The XAVC footage does show a lot of macroblocking, even at full screen on a 4K monitor. The Prores is more detailed and free of the macroblocking, excepting the rectangles of cyan tint over portions of the image.

This artifact really pops out when saturation is boosted.

I have not seen macroblock artifacts on the HQ mode of Prores in normal scenery like nature scenes and cityscapes.

Has anyone else shot the moon and observed artifacts that are difficult to explain the cause of?

Capture.jpg
 
LOL.. I doubt even NASA knows what they are!

For some reason, the image I uploaded got scaled very small, so the artifacts are barely visible.

I'm going to try shooting S-log 2, since it does much better with shooting things like lava lamps and has more steps allocated near the highlights, and see if the quality is better. It looks like posterization to me, but only in specific areas with specific colors.
 
I don't know the answer to your question, but man, that is a really cool shot you got there nonetheless! Really cool. I might try it myself one night. Looks like fun.
 
Which Sigma 150-600 do you have? I just bought the contemporary since i heard its not that big of a difference (optically). Also are you using speedbooster or smart adapter?
 
Here is the whole frame of that image of the moon:

Moon 4-20.00_01_38_17.Still002.jpg

I shot with the Contemporary, not the Sport version. This lens was under $1K. Metabone EF to E mount adapter.

Also caught this the same evening, earlier:



Next time I shoot, I'll use HFR just in case any moving objects traverse it again.
 
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