January 4, 2016 at 10:35PM

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Sony A7S II - Slog3 S-Gamut3 - NOISE ISSUE - test footage

open discussion on solutions for noise in shadows on slog-3.

test footage: https://youtu.be/bngZRqU2J6g
(1080p 24fps on XAVC-S 24,60,120fps - PP9 Slog3 S-Gamut3, exposed +2 stops)

exposed 2 stops over but still experiencing heavy noise in shadows. from what I gather so far the slog-3 is a marketing gimmick on sony a7s ii due to 4-2-0 sampling it crunches to hard and therefore slog-2 should be used, or cine1/4 at night.

8 Comments

When shooting LOG footage with a camera that stores video in an 8-bit format you are trading off low-noise for higher dynamic range, so image noise is unavoidable. The main claim to fame with the SLog-3 format is better skin-tone colors, which seems to be the case from the footage I've looked at.

There's some great info on Sony's LOG formats by Alister Chapman that helps to clarify things. ( check out the LOG section on his 2.5 hour Sony FS5 overview video, links to jump to specific sections are in the YouTube description )

Exposing and Using S-Log2 on the Sony A7S
http://goo.gl/8X8V7F

Vocas Sony PXW-FS5 Introduction days presented by Alister Chapman
https://goo.gl/CBa9bo

January 5, 2016 at 9:47AM, Edited January 5, 9:50AM

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Guy McLoughlin
Video Producer
31777

Thanks for the useful links Guy. I'll check them out.

I've seen some great 'noiseless footage' out there:
http://bodhivisuals.dk/a7s-ii-video/

And wonder about people's workflow to achieve that? I see people are using denoiser plugins and grading... as well as overexposing. Is that it? I would love to get a lovely denoised picture finally!

P.S. this is by far the best guide to the A7Sii I've seen:
http://videoproduction.training/sonya7siiguide.html

He makes the point that SLOG3 isn't better than SLOG2
SLOG3 - better for indoor/ night (non bright scenes) + 2 stops overexpose
SLOG2 - better for bright scenes (as better highlight roll-off) + 1 stop overexpose

Lastly, this guy finds a workaround for the banding issue, which I tested but didn't like:
CINE1/4 - http://www.marienho.com/how-to-use-slog3-luts-for-the-sony-a7s-ii-withou...

Please everyone feel free to share any tips/ thoughts on the above..

January 5, 2016 at 7:44PM

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Rupert S
filmmaker
182

Are you shooting below 12,800 iso? There seems to be a common issue that people are experiencing shooting in SLog between 1,600 iso and 10,000. After 12,800 it cleans up and then going back DOWN the iso levels 10,000 is clean but going down once more and the awful noise is back. The fact that 10,000 iso can be noisey as hell when going UP the iso levels and much much much cleaner when coming DOWN the iso levels spells firmware glitch to me. Time will tell. Sony have been made aware of the situation by many people including myself with a visual reference. They have told me it has been Escalated.....

January 11, 2016 at 11:57AM

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Yeah. i heard that too. weird. lets hope the firmware update addresses that. I also read somewhere that when shooting in s-log you should keep it at native ISO 1600. Anything above and it starts deteriorating into the 14 steps of dynamic range. Something to bear in mind.

I've been doing a lot of s-log tests and just shot a short docu in malaysia on it which I'll share in the next week and my settings/ PP/ etc... But basically, any night scenes i don't shoot s-log as there is just too much of that artefacts/ grain/ banding. I get much cleaner results with cine1 or cine4 (with cinegamma setting).

For daytime, I am now getting better results with s-log 2/3 after applying the ETTR +2 rule and generally getting close to my camera! I mostly shoot on s-log3 as prefer the flatter profile and I have gone from feeling rather frustrated to actually really liking this camera with all its quirks.

Would be good to get some advice on workarounds for 8 bit 4:2:0 sampling. E.g. If converting to pro-res really help at post...

January 16, 2016 at 7:44AM, Edited January 16, 8:00AM

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Rupert S
filmmaker
182

The final result:

http://youtu.be/LD_Xm2Xwwyw

January 28, 2016 at 11:42PM

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Rupert S
filmmaker
182

Here's another test looking at the noise issue, most specifically how dialing up to 10k ISO is much noisier than dialing down from 12.8k IS0.

This is very odd noise performance issue and might point to a firmware issue specifically with shooting S-Log3.

https://vimeo.com/160340989

March 27, 2016 at 7:26PM, Edited March 27, 7:26PM

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Here's another test I ran showing the unbelievably bad noise performance in ISO 10k, but considerably cleaner image at ISO 12.8k.
https://vimeo.com/160340989

Here's the place to complain to Sony about the issue:
http://community.sony.com/t5/Join-the-Inspiration/Please-Fix-a7sII-Slog-...

March 27, 2016 at 7:37PM

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PP9 might be part of the problem - https://www.youtube.com/watch?v=CPfbCKYPT0U

September 7, 2016 at 8:19PM, Edited September 7, 8:19PM

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