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Tuesday, December 11, 2012

••◊ Matching the GoPro Hero 3 Black to a 5D mark II, part4

This should *technically* be labelled "Matching the GoPro Hero 3 Silver to a 60D", but oh well.  It's probably best to keep the title to finish out the series.  My friend Clarence started doing weddings for extra cash (for which I give him a hard time) and for some reason he thought it was a good idea to mix the GoPro's in with his Canon 60D SLR without testing it first.  So he called me up Sunday to essentially say...they don't match up.  I can't edit my footage together.  Just because Clarence knows I'm saying this internally and I need to get it out of my system...."Duh!"

He recorded the GoPro footage using Protune and CamRaw settings.  Because this wedding was outdoors the white balance was actually decent.  No problem there.  As I pointed out in my previous postings, the CamRaw setting is very desaturated.  It's not going to immediately match with anything on a Canon SLR.  Also Clarence was using my calibrated rec.709 custom picture style on the Canon, so I had to match it to that color profile.

Here's the long and short of it...I needed to to a quick and dirty color calibration with the GoPro footage.  I started out by using a "Fast Color Corrector" effect and setting the saturation to 200%.  This got me in the ballpark; not perfect, but in the ballpark.  Then I used the "Channel Mixer" effect with the following matrix...

[ 0.77   0.04    0.16]              [R-gpro]              [R-rec709]
[-0.09   1.15   -0.08]     x      [G-gpro]      =      [G-rec709]
[ 0.15    0.14    0.67]             [B-gpro]              [B-rec709] 
You may want to look at my previous post to see how to apply these numbers into the Channel Mixer.  The color matched up reasonably well.  Not perfect, but we weren't going for perfect.  We were going for not having a noticeable difference when cutting between cameras.  At least I got dinner at a nice restaurant out of the deal.
I know, I know...where are the pictures.  Can't post them.  It's not my footage.


Shawn Caple said...

Stuart, I just stumbled upon this. Great info. I am still very amateur when color correcting. Thanks for posting these blogs explaining your process. Does this process work for the 5Dm3 and hero 3+? Also, I may have missed where your 709 picture profile is or did you not post it for download? Would love to have it to test out. Thank you.

S. Allman said...

The process is the same, but the exact settings for the mark 3 are probably different. I tried my mark 2 rec.709 profile on the mark 3 and it didn't work. Canon changed the format of the picture style files. So unless someone wants to send me a free camera I don't intend to support the mark 3. The C100 is far superior for video anyway.

Shawn Caple said...

Thanks for the response! Would the gopro settings and effects in premiere get the look close to the 5d? I know you used a personal excel sheet and such, does this mean I can't figure out a matching process on my own with any camera? For example the 5dmark3 or the Sony a7s?

S. Allman said...

The process is pretty much the same for most cameras. First, start by adjusting the gamma/tone curve so the two cameras match, then adjust the color. My excel sheet is as close as I get to owning a vectorscope (it does the same calculation). To do this the non-ghetto-fabulous way you want a DSC Chroma Du Monde chart and a vectorscope. The Macbeth chart and excel sheet was the way I did it with more accessible stuff. You can do most of these adjustments in Premiere, but with these fragile 8-bit codecs it's always better to make the majority of adjustments in the camera while the signal processing is still 12/16-bits and before compressing the hell out of the video (as the Canon and GoPro cameras do).

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