Sony A7 users: Filming Clouds in SLog 2/3 on Sony A7sii = green & purple HELL?

[Charles Ryan Mauk]

I've had my A7Sii for few years now, and I love it. Really. Except for when I chase. I try to shoot in SLog for the most dynamic range. It's marvelous in a lot of scenarios and I've used it for various commercial video work and music videos. When shooting in SLog (google that, it'd take WAY too long to explain) on several chases I noticed that when I apply grading using one of several LUTs and then tweaking if needed, there's always this odd color shifting and pixelations in the footage. After doing some research the apparent culprit is that SLog 2/3 doesn't handle the fine variances between greys...like what we're after. Then add the changing lighting with a native 1600 ISO The reasoning is due to the limitations of 8-bit, 4:2:0 formats; 10-bit, 4:2:2 handles this fine apparently (I know what I'M buying come tax time).

After doing some test shots on a partly cloudy day, I think I'm banking on that the way to go is Cine 2 or Cine 3 for picture profiles. It doesn't seem to produce this weirdness from what I can tell.

Question for any of you that shoot Sony - have you encountered this ever? If so is Cine 2/3 better? I have attached some screen grabs of my last chase here to show you what I mean. On a smart phone it's not really apparent but on even a laptop it's painful.

Thanks in advance!

 

[James Hammett]

I can't help with anything Sony specific as I run Panasonic cameras for video. But in general with 8-bit I've found it better to record as close as possible to the desired end result and minimize grading in post - particularly with contrast. There just aren't enough bits available to record flat and perform heavy grading later like you would do with 10+ bit. You'll get banding and other problems especially with our large areas of mid-tone grays as you note. So if Cine 2/3 gets you closer in-camera to where you want to end up after grading that may be the way to go.

 

[Charles Ryan Mauk]

Indeed. Thanks for the insight and yes: I did a little extra diving after I posted this initially and found that that is indeed the case. I’m hoping to get a 10 bit 4:2:2 camera by next year but if not CINE it is

 

[Greg Campbell]

I get obnoxious purple / magenta banding on my A7s stills. Sunset, with dark clouds and a touch of warm light, really brings out the banding. Haven't yet found a real good fix, although tweaking the blue channel's hue toward magenta can smooth the transition.

 

[Dan Robinson]

I've heard and read about some issues with the electronic shutter mode on this camera, including rolling shutter split screen banding just like you see with video on CMOS cameras. I'm not sure if this could be related to the original poster's issue.

 

[Greg Campbell]

It's a color rendering issue that is likely due in part to Sony's RAW data compression. Shooting in electronic shutter mode also shaves 1 bit of data, which doesn't help. Looking at Flickr and elsewhere, it seem that other cameras suffer the same issue, just not to the same degree. Look for a purple/magenta cast on the bottom of clouds, or along a strong, broad bright/dark gradient.