GH4 Closest S-Log2 Setting in the GH4?

Michael Erlewine

Michael Erlewine

Well-known member
I am used to shooting in s-log2 or REC709(800%), in other words grading footage. What would be the closed settings in the GH4 to s-log2 (requiring grading), but delivering more DR? In particular, for 4K recording.
 
Take sharpening down to -5. Bring saturation down too. Maybe -2 or -3. Depends how flat you want it.
 
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If you're recording in-camera just be a little cautious and run some tests first...if you make it too flat you could end up with blocky noise.

I've noticed that I'm ok dropping saturation and contrast all the way, but I go fairly easy on the curves.
 
Ryan Lightbourn said:
If you're recording in-camera just be a little cautious and run some tests first...if you make it too flat you could end up with blocky noise.

I've noticed that I'm ok dropping saturation and contrast all the way, but I go fairly easy on the curves.
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Taking contrast down really makes it flat. I set it to -5 and I think I'm going to back it off to -3. I too like to grade all my stuff but the codec isn't that strong compared to the C300's so dont go to far.
 
Erik Naso said:
Taking contrast down really makes it flat. I set it to -5 and I think I'm going to back it off to -3. I too like to grade all my stuff but the codec isn't that strong compared to the C300's so dont go to far.
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Which makes the Atomos Shogun recording 4K 422 10bit an interesting proposition.
 
Hey Erik, at 4K, it seems like the codec is somewhere around 25mb/s compared to 1920x1080 since we're dealing with 4x the resolution and have 100mb/s, right? So that seems quite comparable to a good AVCHD codec like NXCAM or even the GH2 pre-hack... so when we're talking about how much we can push/pull/white balance in post, that must be a limiting factor.

However, shooting 1920x1080 with 200mb/s ALL-i must be quite similar to capturing in ProRes, right? What's the difference? Isn't ProRes 422 rated at 220mb/s and it's an ALL-i codec... so it would seem that you would have a lot of latitude for color-correction in post using that codec. At least it makes sense to me but we'll have to see what real tests show.
 
It's still 4:2:0. Thats the weakest link for color grading. Not saying it's a deal breaker, but you can only push it so far before it breaks. 4:2:2 gives you more to work with and you can push it harder in post.
 
I think 100mbps is good enough for some jobs but definitely not good enough for major jobs. Atomos shogun is a must.
 
Erik Naso said:
the codec isn't that strong compared to the C300'.
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Is that based on personal experience grading both sets of footage? I ask because theoretically, at least, that wouldn't seem to be the case. The Canon records at only 50 Mb/s, whereas the GH4 records at 100 Mb/s. Further, the Canon records MPEG2, which is half as efficient as the GH4's H.264. Meaning at the same bitrate, H.264 will give you twice the quality of MPEG2.

So comparing 'apples' to apples' (as it were), the Canon records 50 Mb/s and the GH4 records the equivalent of 200 Mb/s. That's a very strong nod in the GH4's favor, regarding footage quality. The only nod the Canon get's is it's 4:2:2 recording in camera, but given the bitrate differences, is that enough to say it's the stronger codec?
 
Jim Simon said:
Is that based on personal experience grading both sets of footage? I ask because theoretically, at least, that wouldn't seem to be the case. The Canon records at only 50 Mb/s, whereas the GH4 records at 100 Mb/s. Further, the Canon records MPEG2, which is half as efficient as the GH4's H.264. Meaning at the same bitrate, H.264 will give you twice the quality of MPEG2.

So comparing 'apples' to apples' (as it were), the Canon records 50 Mb/s and the GH4 records the equivalent of 200 Mb/s. That's a very strong nod in the GH4's favor, regarding footage quality. The only nod the Canon get's is it's 4:2:2 recording in camera, but given the bitrate differences, is that enough to say it's the stronger codec?
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Yes. 4:2:2 has a whole lot more color information. I would take the C300 MXF codec over the GH4's any day at any Mbps. Heck I would take any 4:2:2 based codec over the GH4 or any other 4:2:0 flavor. Again it's not a deal breaker and I'm very pleased with what I'm getting from the GH4.

The high Mbps the GH4 has is whats giving us that sharp moire resistant image. Thats a big deal.
 
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Thanks. I've never had the opportunity to grade 4:2:2 before. I'm amazed at how far I can push my GH2 footage (Moon Trial 7) before it breaks up. It would be interesting to record some 10 bit 4:2:2 off the GH4 and work with that.
 
Yes but it's capturing 4x the resolution, I don't think it's comparable to 100mb/s of 1920x1080 resolution. That 100mb/s is being used to save detail of 4x the data.
 
Resolution and color space are two different things. 4:2:0 color space codecs in the blue channel when pushed to hard with saturation will show banding really fast. Banding will also just be in the image as well and shows up when in post. 4:2:2 will have significantly less issues with banding. The sky is always first to show the banding effect in post processing because it's blue.
 
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Erik Naso said:
Yes. 4:2:2 has a whole lot more color information. I would take the C300 MXF codec over the GH4's any day at any Mbps. Heck I would take any 4:2:2 based codec over the GH4 or any other 4:2:0 flavor. Again it's not a deal breaker and I'm very pleased with what I'm getting from the GH4.

The high Mbps the GH4 has is whats giving us that sharp moire resistant image. Thats a big deal.
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The biggest difference is 10bit out. You'll get 4x color information in comparison to C300.
 
Erik Naso said:
Taking contrast down really makes it flat. I set it to -5 and I think I'm going to back it off to -3. I too like to grade all my stuff but the codec isn't that strong compared to the C300's so dont go to far.
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Interesting, so the C300's MPEG-2 50mbps codec holds up better than the GH4's 200mbps All-I codec?
 
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