GH4 80 IRE in V-Log L

J

Jim Simon

Veteran
I finally had the reason and the funds to upgrade to the GH4, and have also acquired the V-Log L update. (Firmware 2.5)

I see that Zebra 2, normally set at 100% exposure for most profiles, is automatically lowered to 85 for the VlLog L profile. I assume this means that 85 is the clipping point.

Has anyone does the testing/math to determine where 80% zebras will fall with the V-Log L profile? They're not "automatically adjusted" like the clipping zebras are. Put another way, what should Zebra 1 be set to in V-Log L such that when converted to 709, that same exposure will hit 80 IRE on a waveform monitor?
 
Not sure about 80% IRE, but if you set anything higher than 75% on the zebras you will never see them clip, since the clipping point of V-Log L is 79% IRE. I set 75% on the zebras in order to see where the highlights are about to clip, so I can avoid them clipping.

HTH!

Paul :)
 
To answer my own question, I ran some tests and it looks like Zebra 1 set at 60% will translate to a proper 80 IRE exposure for skin tone when shooting in V-Log L. This is not surprising when you consider that I can get clipping zebras to show up at 80%, bot not at 85%. Roughly a 20% translation down at the top end for V-Log.

Having found that out, I want to add that the exposure meter seems to work perfectly fine for run and gun shooting in V-Log L, just as is does in the other profiles. I will probably only need the zebras when shooting in a more controlled environment.
 
Last edited:
@Jim Simon
Clipping point in vlog-l is 79% as Paul mentions....
When you choose vlog profile ,zebra 2 is lowered automatically from 100% to 85% or maybe you meant 80%?

Paul i set my zebras to 80% when using vlog-l and i can see them ,in areas which are clipping...setting at 85% and up ,is when clipping isn't shown...

in addition ,when using assassin and set zebras (in monitor settings) to 80% and up...nothing is shown for clipped areas...i have to use 75% in monitor to see the clipping...
 
Last edited:
soulkeeper said:
@Jim Simon
Clipping point in vlog-l is 79% as Paul mentions....
When you choose vlog profile ,zebra 2 is lowered automatically from 100% to 85% or maybe you meant 80%?

Paul i set my zebras to 80% when using vlog-l and i can see them ,in areas which are clipping...setting at 85% and up ,is when clipping isn't shown...

in addition ,when using assassin and set zebras (in monitor settings) to 80% and up...nothing is shown for clipped areas...i have to use 75% in monitor to see the clipping...
Click to expand...
Weird that you can see 80% zebras in camera. Your Assassin behaves correctly. I'd set 75% in both to be safe :)

Cheers,

Paul :)
 
Interesting findings! Thanks for the info!

If I were shooting with V-log then what zebra percent should I expose face highlights in a controlled interview setting?

FYI, right now I typically aim for face highlights around 70% when shooting with the Natural picture profile.
 
On the DVX200, face highlights on light caucasian skin should never exceed 55, when using VLOG-L. I don't know what the comparable GH4 setting level should be, but I would expect it would be similar.
 
soulkeeper said:
Clipping point in vlog-l is 79% as Paul mentions....
Click to expand...

Well, when I set the Zebras to 80%, they do show up. Which means there is signal at 80%. My thinking is that if it was clipping at 79%, I'd be unable to get zebras when set them to 80% because the signal just wouldn't go that high.
 
Benjobe said:
IIf I were shooting with V-log then what zebra percent should I expose face highlights in a controlled interview setting?
Click to expand...

That was exactly the point of my original question.

Based on my testing, setting skin exposure to 60% in V-Log L will translate to the proper 80% in Rec 709.
 
You must log in or register to reply here.
Back
Top