Magenta color cast on A7RII and A7SII in moderately high ISO and lowish light

[agolex]

Anyone else notice this issue known from the A7S still persists? In higher ISOs (tested 3.2, 6.4 and 12.8K) you get these nice magenta blotches. It's much more subtle in the raw images (used uncompressed), but in video and much more so in JPEG it's pretty ugly. The A7SII is quite a bit better than the A7RII (guess the APS-C crop brings it out more and they probably worked on the S more intensively, because people complained about it in the Mk I), but still noticeable.

Frame Grabs from PotPlayer, straight from camera (tried both SLOG and Cine 2, no big diff):

A7RII, 3.2K ISO, brightness pushed in PS:

A7SII, 3.2K ISO, brightness pushed in PS (cast hardly noticeable):

A7RII, 12.8K ISO:

A7SII, 12.8K ISO:

A7RII Still, 15 second exposure, 6.4K ISO (pushed in LR):

 

[Rand Thompson]

I was looking at the video with the two girls and a guy with the yellow subway train. There is a guy in a Blue colored coat behind them. If you look at the graded footage, there seems to be  some purple in the coat as well. I thought it was just my grade but you can see hints of it . albeit much less saturated in the ungraded footage as well.

Could it just be the fluorescent lights above in the subway?Here is want I am talking about below.

 

 

I brought this up in another thread. I thought it was just due to me over saturating the S-log-3 footage due to my inexperience with it.

[agolex]

I brought this up in another thread. I thought it was just due to me over saturating the S-log-3 footage due to my inexperience with it.

Ah, here we go, saw your post before, but didn't have the cameras back then. My stuff is all Cine, so it's no S-Log issue for sure. It reminds me of the extreme magenta cast of the original A7s, which got horrible in higher ISOs. I don't mind it so much now as you don't notice it in most situations, but it's still an issue.

[Rand Thompson]

I'm working with Vlog-L on the GH4 which has it's own issues with magenta/cyan macro-blocking. I Have only owned the Sony A6000, so I have completely no experience with S-Log  other than the clips Andrew uploaded from the A7sII. Maybe its just some setting in the camera that needs to be changed, hopefully not a continuation of the issue with the A7s.

[Guest Ebrahim Saadawi]

GH4 V-Log magenta shadow blocking was the dealbreaker for me. It's very similar to what's seen here. 

I wonder what's the reason. Codec? Perhaps an external recorder will simply remove the codec coloured macroblocks. 

Anyhow Using neatvideo and taking a profile of the magenta/codec blocks and setting it only to Chrominance NR and 0 Luminance NR gets rid of the issue completely. Slows rendering of course. 

[Rand Thompson]

I think it's pretty much official amongst GH4 owners, myself included, that Vlog-L was meant to be used with a 10-bit external recorder. I'm no techie, but from what I understand from the guys who seem to be much more knowledgable than I , 8-bits is not enough for most LOG profiles. Some disagree and point to canon's C-log 8-bit codec to show that 8-bits is enough, but, hey, i don't know.

[agolex]

I wonder what's the reason. Codec? Perhaps an external recorder will simply remove the codec coloured macroblocks. 

Tried it with the Shogun, absolutely no difference. HDMI output to me seems identical to the internal recording anyhow. I believe it's the same issue as with the A7s Mk. 1, just improved upon. Also think it's not sensor related as the A7RII exhibits it even stronger. Probably just a 'Sony too lazy to work it out'.

These cameras would be so awesome with 10 bit or at least 10 bit HDMI.

Thanks for the Neat tip anyways!