GH5 Color matching - GH5 and BMPCC4K

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Calling new 4K pocket cam owners (who ideally also use GH5).

Have you any experience color matching these two? Would it be practical to use the Blackmagic as an A cam and GH5 as a B cam for sit down interviews?


The BM seems impractical on a Ronin S and would be happy to keep the GH5 form factor for gimbal use.

Thanks!
 
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I've got one on pre-order so as soon as I have it in hand I'll build a corrective LUT to match it exactly to Rec709, as I have done with my GH5 LUTs :)

HTH!

Cheers,

Paul :)
 
I'll have both (as soon as my P4K arrives) and will be testing just this. I would be SHOCKED if they cannot be made to intercut reasonably well, especially if dynamic range is kept within the GH5's window and the same lenses are used on both cameras. My guess is that in addition to matching/corrective LUT's, the GH5 footage will need a very slight softening to take off the edge from the in-camera sharpening.
 
Shirozina said:
Also achievable using Resolve Color Management as long as you use HLG for the GH5 capture.
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To clarify, it'll be a precise match at every point in the color space, as measured sensor to sensor. This is where RCM has its limits :)
 
Sage said:
To clarify, it'll be a precise match at every point in the color space, as measured sensor to sensor. This is where RCM has its limits :)
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HLG uses a defined colour space model ( unlike the mysterious V- gamut) and presumably BM know the precise colour model of their cameras so doing a mathematical transform in a 32 bit working space between the 2 should do the job very well - presuming camera to camera variations are not too great.
Now that’s only the transform of the color space but depending on other factors the P4K may still be better in it’s ability to differentiate between subtle hue differences which in the narrow gamut range of skin tones may mean differences are visible. Just like the difference between an Alexa and a GH5 where it’s mathematicaly possible to match the color models shape it’s not possible to invent the missing data in the GH5 where it can’t differentiate the fine hue values that the Alexa can.
 
Shirozina said:
HLG uses a defined colour space model ( unlike the mysterious V- gamut) and presumably BM know the precise colour model of their cameras so doing a mathematical transform in a 32 bit working space between the 2 should do the job very well - presuming camera to camera variations are not too great.
Now that’s only the transform of the color space but depending on other factors the P4K may still be better in it’s ability to differentiate between subtle hue differences which in the narrow gamut range of skin tones may mean differences are visible. Just like the difference between an Alexa and a GH5 where it’s mathematicaly possible to match the color models shape it’s not possible to invent the missing data in the GH5 where it can’t differentiate the fine hue values that the Alexa can.
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Right.

I would highly recommend Resolve users to use RCM (or ACES) instead of ressorting to LUT 'magic'.
 
Cary Knoop said:
Right.

I would highly recommend Resolve users to use RCM (or ACES) instead of ressorting to LUT 'magic'.
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- RCM provides a really good starting point, "normalizing" the different cameras' footage, but it doesn't go all the way to trying to match it. A "corrective" LUT (one that does not try to impose a style, rather brings different cameras to a common base) is a good, quick way to take it the last mile.

- I would guess (only a guess since I don't have the P4K) that HLG would be a poor choice on the GH5 if the goal is to intercut with the P4K. While many (myself included) use it as a poor-man's LOG, it's got a bunch of other stuff going on that will only serve to complicate a match. V-LOG L will likely be a better choice.

- Do NOT rely on FilmConvert to match cameras. On paper, it seems like the ideal easy solution. They supposedly profile every camera. It *should* be easy-peasy to both correct and stylize your footage in one fell swoop. (That final pass applying a "look" really goes a long way to tying different footage together.) BUT...I don't know what the hell FilmConvert actually does in profiling, because if you apply it to the same scene from two different cameras, they don't match...at all.
 
Cary Knoop said:
What other stuff are you talking about?
HLG works great much better than the crippled and gamut incorrect V-Log-L for V-Log/V-Gamut.
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Reliance on video levels is a good example of what I'm talking about. I'm not suggesting it is bad, just that going from one simple log curve to another simple log curve is a more direct approach, with less room for error.
 
joe12south said:
Reliance on video levels is a good example of what I'm talking about. I'm not suggesting it is bad, just that going from one simple log curve to another simple log curve is a more direct approach, with less room for error.
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Interpreting correct levels and using good color management make those things complete non-issues.
 
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