miko meloni
Active member
One question: how to expose skin with Clog? Up to 70ire, or (how much) less?
C100: Canon Log - does it do anything other than compress the data?
- Thread starter stevedocmaker
- Start date
Dino
Veteran
18% gray should be at 38 IRE, reflected white at 70 IRE, therefore skin tones would be lower, more in the 50% range.
IMO, gammas should be chosen like film stocks. Low contrast stock(Cine gamma or C-Log) for high contrast scenes, high contrast stock(Norm, EOS Standard) for low contrast scenes.
Resolve has a preset C-Log curve, so is very easy to grade, as least as a starting point, but I've seen mid blacks get noisier due to shooting C-Log.
Regarding Adam Wilt's testing, I know Adam, I've been present during his tests using DSC back lit charts and have seen for myself his results. The pre-production FS700 he tested had 14 stops of DR. It also had less resolution horizontally than a C300 and some artifacts in high to low contrast transitions, such as the vertical edges of windows that you won't see with a C300. It moires with verticals, C300 moires with tight horizontals. C300 has a more polished, sophisticated image than FS700, which is noisier with much larger pixels.
AndreeOnline
Veteran
The high tones says pretty much in place. Sure, everything moves a little, but it's minimal at the top end.
Let me rephrase a more specific question directed at anyone: if you are a Log lover, do you:
- expose Log "correctly" and let most of your image fall below IRE 50 and then lift in post and accept the added noise with a shrug of your shoulders...
- expose Log with 'View Assist', looking at the screen and overexpose so that the image looks pretty good already at capture...
The interesting thing is that Canon has devoted an article to their Log on their digital learning center and there's the white paper.
But reading both of those, the explanation they offer is "...you have to chose the right bits. We have done that".
Everything else is broad general strokes.
philiplipetz
Veteran
I have had good success exposing to just below 100 for highlights and then bringing up shadows in post.
Where did you hear this? Got any links?
MattDavis
Well-known member
I'm really excited yet apprehensive about C-Log.
We're working in an 8 bit environment, after all. To me, that means we have to be close to end tonality because if we pull and stretch tones too far from their starting point, we're pulling taffy. It breaks apart with a robo-dapple pattern on the WFM if we push too far. I've yet to commit to doing C-Log on my Pix220, and I'm sure it will be better, but Wide DR is doing it for me at the moment.
I got the impression that Canon has jiggled the gamma to map tones from the sensor to levels in the AVCHD codec and we back off and trust Canon. In really bright contrasty situations (sunlight, high key interiors with windows), yes - C-Log is exciting and I can work with it. Most other times, Wide DR is like shooting with Black Stretch and CineGamma on Sonys. Use the WFM, skin at 60 IRE, minimum jiggling in FCPX, and we're done on Primary correction.
Over in the FS100 camp, we're ranting that Picture Profiles are like Spaghetti Sauce - you can't have just one to rule them all. You need several, according to your conditions. I doubt C-log will be very handy for, say, office lighting or chromakey. But I've already seen the joy it brings to impossibly contrasty lighting.
We're working in an 8 bit environment, after all. To me, that means we have to be close to end tonality because if we pull and stretch tones too far from their starting point, we're pulling taffy. It breaks apart with a robo-dapple pattern on the WFM if we push too far. I've yet to commit to doing C-Log on my Pix220, and I'm sure it will be better, but Wide DR is doing it for me at the moment.
I got the impression that Canon has jiggled the gamma to map tones from the sensor to levels in the AVCHD codec and we back off and trust Canon. In really bright contrasty situations (sunlight, high key interiors with windows), yes - C-Log is exciting and I can work with it. Most other times, Wide DR is like shooting with Black Stretch and CineGamma on Sonys. Use the WFM, skin at 60 IRE, minimum jiggling in FCPX, and we're done on Primary correction.
Over in the FS100 camp, we're ranting that Picture Profiles are like Spaghetti Sauce - you can't have just one to rule them all. You need several, according to your conditions. I doubt C-log will be very handy for, say, office lighting or chromakey. But I've already seen the joy it brings to impossibly contrasty lighting.
Apologies there - I picked FS100 not 700.
I stand by my other points that I made.
There is no "DATA COMPRESSION". A flatter "log" curve is applied.
Ive tried and seemingly failed at a few attempts to point out Canon Logs ease of use and the positives of using it. I wont go on beating a dead horse here.
AndreeOnline
Veteran
I actually read it on Technicolor's own site when CineStyle was launched. But they have a dedicated CineStyle site now with new info.
There are traces in their FAQ referring back to what I mean: the CineStyle was made for Technicolor's own pipeline to allow for intercutting—as good as possible anyhow—between the 5Dmk2 and film or other higher end cameras (Log workflow).
I do want to clarify that even if it wasn't meant to be a general purpose profile, that in itself doesn't mean that you can't use it as such. But we come full circle back to the current discussion about Log profiles into an 8 bit space.
AndreeOnline
Veteran
I don't want to put words into someone else's mouth, but I think what is being referred to here is the fact that due to Log's equal data priority per stop of light, an unusual amount of our 8 bit resolution is devoted to shadows and highlights. That's fine in 12 bit and probably in 10 bit, but in 8 bit it's more of a give and take.
Yes, we get to record detail that would potentially be lost otherwise, but at the same time we end up with less precision in potentially crucial mid tones and skin.
Looking at the waveform you see much of your information clamped together between 20-50 IRE. I think this is the "compression" that is meant here.
Speaking for myself, I agree with you that it is a total non issue to add contrast and set white and black points in post. I'd gladly to that in return for a better picture.
In my case it's more a question of consequence: does 8 bit have what it takes to handle the workflow?
Stephen Mick
Totally Usable
The 8-Bits of the C300 going to 4:2:2 XF Codec most certainly does. The 8-Bits of C100 4:2:0 seems to be the question in many people's minds.
Actually, the 8-Bits of the C100 recorded with a Ninja2 to 4:2:2 is the question in my mind...
AndreeOnline
Veteran
The C300 codec is better for sure, but I'm not sooo concerned about color precision with internal recording. I don't do green screen or excessive grading. Also have a better 4:2:2 than the C300 via HDMI out, even if it isn't as nice as if it were onboard from the beginning.
It's the 256 levels of 8 bit itself that is up for discussion. To distribute 12 stops logarithmically gives us only 22 levels per stop. I don't think Canon Log is perfectly linear per stop, but still...
stevedocmaker
Well-known member
I completely agree with your point about highlight retention. And the more I experiment with C-log the more I like it. I've been tweeking my profiles and developing a log profile that might be my go-to. If someone doesn't start a custom profile thread soon I will, as soon as I've got something dialed in.
One other issue I have with log is judging exposure. It's not easy - problematic in any run and gun situation (I don't find the "view assist" feature very accurate), so wide DR is probably a safer bet in those situations.
They are both good gamma profiles with excellent DR, I just wish Canon would lay off the hyperbole in their manuals & marketing materials.
Latest tests below, both have a light grade (luma curve & saturation). Personally, I like the blown highlights in the WDR clip, but I like the color and overall tone in the log clip. However, the Log clip is noticeably noisier.
Wide DR:
C-Log:
One other issue I have with log is judging exposure. It's not easy - problematic in any run and gun situation (I don't find the "view assist" feature very accurate), so wide DR is probably a safer bet in those situations.
They are both good gamma profiles with excellent DR, I just wish Canon would lay off the hyperbole in their manuals & marketing materials.
Latest tests below, both have a light grade (luma curve & saturation). Personally, I like the blown highlights in the WDR clip, but I like the color and overall tone in the log clip. However, the Log clip is noticeably noisier.
Wide DR:
C-Log:
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Erik Naso
Veteran
I shot this in Canon Log at 850 ISO with the C100. Noon bright sun in the background with the talent in the shade. Used a bounce board to fill a little. I really needed more but I think it looks pretty good. The DR helped. I'm not used to being able to get this shot, and when the producer called for it I was hesitant but gave it a go.
To see the image bigger click on the links.
Ungraded.
http://farm9.staticflickr.com/8360/8272682289_6ac90c0709_h.jpg
Graded with Colorista II
http://farm9.staticflickr.com/8218/8273747812_06bf738c22_h.jpg
In this grade I did get chroma noise but only in the purple jacket. I added Denoiser and it cleaned it up very well. The ISO noise isnt like digital noise (RGB flakes) you see with most cameras. It has a more organic grain to it and cleans up very nice.
I have three masks in the grade.
One overall grade. Curve and saturation.
Second is a third of the image on the right. Mostly the top two talent.
Third is the left upper in the full sun.
To see the image bigger click on the links.
Ungraded.
http://farm9.staticflickr.com/8360/8272682289_6ac90c0709_h.jpg
Graded with Colorista II
http://farm9.staticflickr.com/8218/8273747812_06bf738c22_h.jpg
In this grade I did get chroma noise but only in the purple jacket. I added Denoiser and it cleaned it up very well. The ISO noise isnt like digital noise (RGB flakes) you see with most cameras. It has a more organic grain to it and cleans up very nice.
I have three masks in the grade.
One overall grade. Curve and saturation.
Second is a third of the image on the right. Mostly the top two talent.
Third is the left upper in the full sun.
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This makes no sense.
I read everything released by Technicolor when the profile was released. They did not specify what you say they did, and they certainly could not have been surprised by number of downloads before launch.
Erik, that shot looks great, particularly as you are shooting into shade with bright exposure in the BG.
AndreeOnline
Veteran
To you.
Dito. For me.
No, here I agree. That sounds like a retarded thing to say. Where did you read that?
Well it's nice if you are talking to yourself, but most people like to be logical to others too when we speak.
That's what you said. I asked where you heard that and you said on their website at launch. No such thing was posted at launch, and if they said it since I'd like to see where.
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Took me awhile, but I see where you guys are coming from considering Stephen spelt it out. Well you guys with the c100 keep working on it and let us all know.
Think Erik's images show a solid result however. (Also could be that Ive never seen something from Erik that didnt look solid).