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C300 Artifact Encode Issue

c300 color color grade encode youtube cinematography c-log log canon blacks

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#1 Tyler Clark

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Posted 12 November 2014 - 07:22 PM

I have been having an issue when color grading lately with the C300. 

 

After the grade, most blacks that are below 40 IRE seem to be artifacting like crazy on youtube. Whereas I don't see this from other people's work. 

 

Ive tried these encode settings in adobe media encoder,

 

Quicktime MOV, h264

55'000 kbps

1920 x 818

 

Quicktime MOV, h264

35'000 kbps

1920 x 818

 

Quicktime MOV, h264

25'000 kbps

1920 x 818

 

Quicktime MOV, Prores 444

1920 x 818

 

But all of them just aren't cutting it and I dont know what I'm missing. My blacks are generally not brought down to 0 because the director wants a low contrasty look and some scenes were shot very dimly with only one LED to light the scene.  On the other hand, we've lit darker scenes with several 1k's and Litepanel LEDs and while the highlights and midtones held up the blacks still artifacted hard. 

 

Here is an unlisted link to a test video I made. Please don't share outside of the community. 

 

 

Any and all info would be much appreciated!


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#2 David Mullen ASC

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Posted 12 November 2014 - 08:25 PM

If your video test is just that noisy black field, I don't really see compression artifacts like macro blocking, I just see noise.

 

Running the video through noise reduction would make it easier to encode for youtube.


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#3 Tyler Clark

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Posted 12 November 2014 - 10:57 PM

Is there any way to get rid of that aside from simply adding more light?


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#4 Tyler Clark

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Posted 12 November 2014 - 11:17 PM

If your video test is just that noisy black field, I don't really see compression artifacts like macro blocking, I just see noise.

 

Running the video through noise reduction would make it easier to encode for youtube.

 

Do you have any recommendations or advice on how to approach that from lighting standpoint to get a similar result I guess is my question. 


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#5 David Mullen ASC

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Posted 12 November 2014 - 11:32 PM

Noise comes from underexposure so you need to use a lower ASA rating and get more light to the sensor, either with faster lenses, longer shutter times, and/or more lighting. Particularly if you are going to time the image with lifted blacks.
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#6 Tyler Clark

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Posted 14 November 2014 - 11:06 AM

Noise comes from underexposure so you need to use a lower ASA rating and get more light to the sensor, either with faster lenses, longer shutter times, and/or more lighting. Particularly if you are going to time the image with lifted blacks.

 

I understand that. I guess what I'm mostly concerned with is, what part of the waveform is considered underexposed? Would using a lower ISO rating than the C300's native ISO be beneficial or will it create more noise? And lastly does having lifted blacks garner more noise in the image? The canon records its log at around 20 IRE and I have been leaving it around there however it seems that I am getting more noise when I bring the blacks down than I get when I just leave them. 

 

We wanted to leave alot of black in frame (similar to later episodes of law and order SVU) but I'm trying to figure out how to handle that in camera and in our setups. 


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#7 David Mullen ASC

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Posted 14 November 2014 - 11:35 AM

I don't see how taking the blacks down from 20 IRE to 0 IRE would increase their noisiness.  Why would a lower ISO rating increase the noise either?  All of that is backwards.  Maybe your color-correction system is screwing up the footage in some way?

 

I will say that you can't really go much lower than the native ISO in the Canon because the dynamic range drops quickly.

 

In terms of real world shooting, you may be running into the limitations of its internal 8-bit recording, which limits your range of color-correction for misexposure.


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#8 Tyler Clark

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Posted 14 November 2014 - 01:00 PM

With the 8-bit issue I see that in the MOV file that is exported?
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#9 Sabyasachi Patra

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Posted 14 November 2014 - 01:07 PM

 

I understand that. I guess what I'm mostly concerned with is, what part of the waveform is considered underexposed? Would using a lower ISO rating than the C300's native ISO be beneficial or will it create more noise? And lastly does having lifted blacks garner more noise in the image? The canon records its log at around 20 IRE and I have been leaving it around there however it seems that I am getting more noise when I bring the blacks down than I get when I just leave them. 

 

We wanted to leave alot of black in frame (similar to later episodes of law and order SVU) but I'm trying to figure out how to handle that in camera and in our setups. 

Middle grey is around 32 IRE. If you are using 20 IRE then you are underexposing and hence the noise. 


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