c300 - C-Log - completely inaccurate colors! Do we have a bad unit?

I just remembered, also - AbelCine's scene files for the C300 have a color correction setting in the CP menu to compensate for the green shift in the yellows of the C300's standard gammas. I'm certain it wouldn't be too hard to make a similar color correction for the teal-green in a custom C-Log profile so that it doesn't shift into cyan. You could also do another one for reds if they're a bit to orange for your taste (although according to my vectorscope, reds are landing in the right spot in C-log) and use them both together since you have an option for Area A and Area B color corrections and can use one or the either or both at the same time.

With the C300, there's a myriad of options for creating the look you need within camera. I have a feeling that a little time and testing would yield perfectly acceptable results for just about any situation. And the good news is that it seems many corrections can be made without affecting skin tones, which I feel are very nice in all the gammas and matrixes.
 
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I've gone back and taken screen grabs from my Leader LV-5330 scope of the various Canon supplied matrix options. I also included the matrix settings that I did a few months ago to try to get closer to REC709. I didn't post them here because this site doesn't accept .bmp files. Please go to this link:

http://www.cinemaeosuser.net/index....atrix-color-points-none-of-them-are-accurate/

As you will see, none of the Canon matrix options are accurate for REC709, and I didn't find any Abel Cinetech scene files that were either. This is not surprising as each matrix option is going after a look, not accuracy, but I'd really like to have a true REC709 scene file. I'll keep working on mine, as I'm not happy with it. Clearly I have to learn how to use the Color Correction controls.
 
When I used to shoot still fashion, I had a pair of orange plaid pants that were almost impossible to capture accurately.

I was able to use my Xrite i1 Pro software to profile the camera - and it absolutely nailed the colors. I always worked with a fully profiled chain, from input, to monitor, to output after that.

Now, of course you often want pleasant color rather than perfectly accurate color. But being able to get to the same, accurate, baseline starting point in any color space or Picture Profile should let you tweak the settings in a known direction to achieve the colors and "look" that you are after.


The Xrite i1 Pro software will create a profile off of a single frame grab of a MacBeth Color Checker. Basically, it compares the camera recorded value to the known, correct color value and creates an .icc profile taht you apply in Photoshop, Lightroom, etc.

This is based around a RAW workflow. You could use your C Log as is from teh camera and apply the profile in Photoshop on the video layer to do the color correction in CS6.

Conceptually, you could also use the values that the software detects, and the variance from the known values, to tune your LUT/Color Correction in camera. You might do this in an iterative fashion - capture video, grab a frame, run the software to analyze, then tweak teh LUT/Color Corrections again to ensure that you are getting progressively closer to accurate values.

There is also 3rd party camera calibration software available that will analyze the Color Checker image and give you a table of offset values from the known value.

I am not familiar with the C300, so I can't talk to any of the specific details of calibtrating that camera.


I have the origional version of the Xrite i1 Pro Extreme. There is a newer i1 Pro II that was released just this year. Those packages will create an .icc profile
for a camera.

OK, it looks like XRite also offers the Color Checker Passport as their newer camera calibration software. This does not require the purchase of the Spectrophotometer and the Xrite i1 Pro II software kit.

You can download it free from Xrite and use it with your Color Checker:

http://xritephoto.com/ph_product_overview.aspx?action=support&id=1257



The alternative would would be to capture an image of the MacBeth Color Checker (or similar tool - Kodak Q60) and manually compare the Photoshop RGB value to the known, published value and adjust the LUT accordingly. This is obviously a more time consuming and interative process.


It looks like you have the 24 square Xrite "Color Checker Classic." There is a table of the correct values for the Xrite target here:

http://xritephoto.com/documents/literature/en/ColorData-1p_EN.pdf



Best,
Michael
 
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Dino said:
I've gone back and taken screen grabs from my Leader LV-5330 scope of the various Canon supplied matrix options. I also included the matrix settings that I did a few months ago to try to get closer to REC709. I didn't post them here because this site doesn't accept .bmp files. Please go to this link:

http://www.cinemaeosuser.net/index....atrix-color-points-none-of-them-are-accurate/

As you will see, none of the Canon matrix options are accurate for REC709, and I didn't find any Abel Cinetech scene files that were either. This is not surprising as each matrix option is going after a look, not accuracy, but I'd really like to have a true REC709 scene file. I'll keep working on mine, as I'm not happy with it. Clearly I have to learn how to use the Color Correction controls.
Click to expand...

Seems to me Canon video cameras have tended to shift saturated reds toward orange for years. My old GL2 does the same thing. Stoplights always come out looking orange for instance.
 
I've started a dialogue with the Pro Department at Canon Canada.

Surprisingly, they've never heard of any issues with color in the C300. They're working hard at the moment to try and help us calibrate our camera so that it reads color accurately.

I'll report what conclusions we come to together.
 
Spurred by this thread, I've spent the last week tweaking and testing some new color profiles for the C300. I've finally got a recipe that gives what I think is the most accurate colors I've seen from the camera: red's don't go magenta or orange in stoplights or taillights, yellows don't have a green cast, light greens don't skew cyan, and there is no red tinge in blue skys. Skin looks great, and colors appear natural and true. Based on the recipe, I've got three profiles that I'll release to morrow: TRUvid2, TRUcine, & TRUlog. I'll try to get some sample framegrabs from TRUvid2 up tonight before my flight back to LA.
 
cowpunk52 said:
I've got three profiles that I'll release to morrow: TRUvid2, TRUcine, & TRUlog. I'll try to get some sample framegrabs from TRUvid2 up tonight before my flight back to LA.
Click to expand...

Wow! Happy to spur! Can't wait to try the same tests with these profiles! You're a godsend Brian!
 
I got a reply from the Canon Canada pro department regarding the color inaccuracies in Cinema Lock Mode.

The rep stated 'That's just the way the camera is. It's up to the user to deal with in post.'

The rep also stated he'd leave the case open.
 
This reminds me of Canon's response to complaints about color fringing in extreme highlights. My impression is that they believe the camera has very good dynamic range and color accuracy, but it is not perfect, and the user should just find ways to deal with it. Not exactly the answer you want to hear.
 
Well, no camera is perfect and users should try to find the best ways of dealing with each system's imperfections. But yeah, not the answer you want to hear.
 
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