C100: Why is Canon log betraying me!!?

R

RZE

Active member
I posted a couple times about the c100, the noise floor, and detail in the darks. It is the biggest weakness and I have been trying to find my way around it. This is yet another effort to see what others are doing. Here's my problem, cannon explains that you should shoot at 32% IRE for middle grey in canon log to get the most "highlight retention." In that scenario you get 5.2 stops in the highlights if you count up to 109% IRE, but what about under middle grey. I've done some testing and the noise floor is difficult to define. Looking at 32 IRE middle canonlog the noise floor is maybe at 3-4 stops down, which is nice placing this camera close to higher end cameras, BUT the noise floor shifts when you normalize the footage and bring middle grey back to 50 IRE from 32 IRE. I'm getting noisy low detail darks only 2 stops under middle grey once normalized. Why would canon recommend an exposure range of 5+ and 2-, maybe this is not a concern on the c300 but I don't have one to test. The big gamma shift you have to give to the footage to restore middle grey is to large even for Prores hq 422 in my opinion. I'm done with 32 IRE. Many have labeled red as falsifiers of dynamic range but the c100 is guilty of this as well. Its my opinion that this camera has a 8 stop usable exposure range though it has 12 stops of dynamic range. The only solution where I have been able to get balanced detail in the darks and highlights in canon log has been overexposing by two stops. Its around 48% IRE so the gamma remapping is minimal and the image is really clean and you have about a 4 stop range underneath middle grey which is not bad, the bad side is that you loose 2 stops in the highlight making your exposure range 3+,4- which isn't that great. All my testing was at 850 ISO. I would love to be wrong about this, help me out!
 
Are you shooting in a run and gun situation? Or do you have time to light? I personally go off my view assist and dial in what I think is correct. C300 user
 
Have you tried exposing 18% gray at 38-40 IRE? Might be a useful compromise. I did a quick dynamic range test for highlights with our C300 next to a Sony F5. I got about 4 stops out of C-Log and between 5 and 6 stops with the F5 in S-Log2. I've seen noisy mid-blacks after grading of C-Log as well. I try to stay with Cine 1 or Cine 2 when there is a bit of contrast control in a scene vs. defaulting automatically to C-Log, but that's mainly because I don't know who's grading most of the time.
 
Dino said:
Have you tried exposing 18% gray at 38-40 IRE? Might be a useful compromise. I did a quick dynamic range test for highlights with our C300 next to a Sony F5. I got about 4 stops out of C-Log and between 5 and 6 stops with the F5 in S-Log2. I've seen noisy mid-blacks after grading of C-Log as well. I try to stay with Cine 1 or Cine 2 when there is a bit of contrast control in a scene vs. defaulting automatically to C-Log, but that's mainly because I don't know who's grading most of the time.
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I'm getting the same results for 40 IRE, 4+ but I'm only getting 3- before I hit the noise floor. The 5d gets 3.5+,3-. I'm disappointed with only a .5 stop extra of usable DR
 
I expose the canonlog higher as well, 1 - 2 stops as you suggest, because like you, I get a lot of macroblocks and noise after normalisation if I expose at the recommended values.
 
Is it possible to do Shane Hurlbut's cinestyle trick on DSLRs (to expose your shot in a "normal" gamma, and then simply switch to a LOG profile for filming?)
 
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Everything Ive read and everything Ive been told = C100 operates best in AVCHD in the wide DR setting. With the ninja 2 - Canon Log.
 
drummondb said:
Is it possible to do Shane Hurlbut's cinestyle trick on DSLRs (to expose your shot in a "normal" gamma, and then simply switch to a LOG profile for filming?)
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That would put you at 32IRE, you'd have the same problem
 
Noel Evans said:
Everything Ive read and everything Ive been told = C100 operates best in AVCHD in the wide DR setting. With the ninja 2 - Canon Log.
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I shot with a samurai and a black balanced c100 in canon log, the camera has some great features, but a lot of competition is noiseless and compresses well on the web, this camera has to shoot in some ideal circumstances to be noiseless
 
Really? That's disappointing to hear. It just doesn't seem possible given that the C100 is supposed to deliver the same image quality as the C300, which is the most popular rental camera in the market. If the C300 didn't deliver, people simply wouldn't rent it again - not like purchasing one and being quasi-stuck with a purchase you're not happy with. Some even say the C100 w/ Ninja2 produces a tad better image than the C300 with the internal codec. Granted they'd produce the exact same image if the C300 was on a Ninja2 as well.
 
digitalinnovations said:
Really? That's disappointing to hear. It just doesn't seem possible given that the C100 is supposed to deliver the same image quality as the C300, which is the most popular rental camera in the market. If the C300 didn't deliver, people simply wouldn't rent it again - not like purchasing one and being quasi-stuck with a purchase you're not happy with. Some even say the C100 w/ Ninja2 produces a tad better image than the C300 with the internal codec. Granted they'd produce the exact same image if the C300 was on a Ninja2 as well.
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Where have they tested darks detail and noise floor on both cameras, I think it is not realistic just based on price to expect the c100 to operate even with the ninja like c300. The scarlet records super clean through the hdmi, why doesn't the c100 when the c300 is clean in smaller codec. The camera is crippled as far as I'm concerned and the images are not the same. Theres a difference of at least a stop in my opinion in usable DR between c series cameras, but I can't prove it because I don't have a c300.
 
I know this isn't textbook, but if you expose Canon Log so that it looks good on the LCD (no view assist, but a good looking flat image)... then you're on easy street.

I don't think 8 bit, Log, AVCHD is something you want to over think. My first experience with my C100 was a shoot shortly after I had gotten the camera. I trusted what I had read and what the manual said so I put 18% gray low as well. Had to push gamma in post. Not doing that again.

I have since had good experiences with View Assist off and just exposing off the LCD to my liking; keeping in mind that I don't want to lift my mid tones in post. At least no huge amounts.

Using Log is always going to be difficult in 8 bit space. But I'm not seeing the issues, such as plasticky skin tones, with Canon Log that I do with Cinestyle from Technicolor, even if I expose it higher than 33%.

That said, I've come to appreciate the Wide DR profile. It's got the same 12 stops and follows a traditional gamma much higher along the curve before flattening out. And it still has nice roll off.

I'm going from mk3+C100 to a 1Dc and I really hope they can bring Wide DR over to that camera at some point. I'll probably stay in Neutral for most shots until then.
 
yes I've found C100 on a Ninja 2 and C300 to be virtually identical... but only when matched with Brian Weed's profiles and shooting C-log. I don't like Wide DR - it's noisier for sure. I used it on a recent shoot and wasn't pleased. I went back to C-log only off the C100 with the Ninja 2 and it intercut identically with the A-cam C300 I had there.
 
You gotta be more specific about the conditions that you shot it. If there was plenty of light and low contrast, then there is no surprise there. There are variables like where was middle grey exposed, what sort of deloging took place, and what was the exposure range of the shots that will determine whether there will be a visible difference.
 
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