C100: LUT for C-Log and tips for exposure

N

nickbeef

Active member
For simplicity sake, I usually shoot my C100 in "Wide DR" picture profile. Looks good right away, but looks even better with a little color correction. I usually don't want to create more work for the editor down the line.

However I have a couple of shoots coming up that I will be producing, shooting, and editing myself. I want to start using the "Cinema" Canon Log profile in my workflow. However, I don't see a C100 LUT profile in Premiere Pro. Sure I can get decent results by just moving the sliders around myself, but is this the right approach?

Also, any tips on exposure when using C-Log? The image comes out looking underexposed, so should I over expose slightly? I use the "Camera Assist" feature to correct it in the LCD screen, so should I just judge based on that image?
 
I follow Shane Hurlbut's guide and it works great for me (though I normally shoot WDR also.) I expose skin tones at 50-65 IRE. Canon says 30-35 but that's too underexposed IMO for C-LOG. You'll end up adding a lot of ugly noise trying to boost your midtones. Be careful not to clip your highlights though. The 8-bit codec won't be able to recover any lost highlight info. It's tricky at first but I think Shane nailed it. I recently shot a short film and followed his settings and was quite happy with the results.
 
I've been struggling with c-log for years, but I think I've finally cracked it.

Firstly, I shot some tests with a light meter, and it suggested to me that when shooting c-log, and grading with the help of a canon LUT, I want my skin tones about 50 IRE, or maybe even a smidgen under that. Here's that test: https://vimeo.com/bobdrummond/review/157318638/660b03a592

When you shoot, shoot with the "view assist" on. You'll start noticing when you're overexposing, especially skin. That in conjunction with the knowledge that you want skin peaking around 50 IRE on the waveform should get you in the ballpark.

When editing (I use Premiere Pro) drop the "lumetri color" effect on an adjustment layer above the video layer. Use one of the canon LUTs found here: http://blog.abelcine.com/2013/12/04/canon-luts-for-the-c100-c300-and-c500/

I like "CxxxLog10toRec709_Full" but you could try the "CxxxLog10WideDR_Full"

If you need to adjust exposure further, drop a color correction effect on the video layer beneath the LUT adjustment layer. I like Colorista III.

Your milage may vary. Here are some of the projects I've shot lately using this method, and I'm quite happy with the results:

https://vimeo.com/user44952203/review/166193013/65309ddcce

https://vimeo.com/user21442843/review/158445420/6f165139aa

https://vimeo.com/bobdrummond/review/165391387/f042da74cf
 
drummondb said:
Your milage may vary. Here are some of the projects I've shot lately using this method, and I'm quite happy with the results:

https://vimeo.com/user44952203/review/166193013/65309ddcce
Click to expand...

Wow, really love the look of the wedding video! Feels very cinematic to me, even though I usually don't like to use that term!
How much "C100" is in there or in other words, did you do anything special besides applying the LUT and fixing exposure/contrast?
 
MichaelFischer.at said:
Wow, really love the look of the wedding video! Feels very cinematic to me, even though I usually don't like to use that term!
How much "C100" is in there or in other words, did you do anything special besides applying the LUT and fixing exposure/contrast?
Click to expand...

Thanks! Yes, I also used some retro diffusion filters to approximate the look of my beloved films of the 70's and 80's. In this case most of the shots have some flavor of fog filters on the front of the lenses.

And I don't know I would describe the Colorista tweaks as "brightness & contrast adjustments" per se. On the video layer under the LUT, I'm usually using the 3-way color wheels in Colorista to simply raise or lower the shadows, midtones, & highlights. Maybe dial the saturation up and down a bit. I don't really know what I'm doing. Just a caveman bashing away here.

This is a good example, in front of the stained glass window. I exposed in camera using the waveform monitor to keep as much of the highlight detail as possible. SO when I dropped the LUT on, it clipped much of those highlights. So I dropped Colorista on the video clip itself and was able to lower the highlights before the LUT did it's job. I obviously didn't have a chance to do an A/B comparison, but I'll wager no other profile, even WideDR would allow me to keep all the highlights while still creating a pleasing overall exposure.



In that screen grab it may look as though the C100's 8-bit codec is falling apart with all my adjustments. I should note I don't see that on my decently calibrated HDTV sets.
 
drummondb said:
Thanks! Yes, I also used some retro diffusion filters to approximate the look of my beloved films of the 70's and 80's. In this case most of the shots have some flavor of fog filters on the front of the lenses.
Click to expand...

Ah that's the secret! Very nice!
The combination seems to work really well! Felt a little retro immediately and I was wondering what kind of lens you were using, because of fall the flare coming from the highlights!

Regarding your method and screenshot: That's why we record in log, to have more leeway in post for adjustments. Even though you think you might act like a cave man, it's actually a solid approach. Applying a proper LUT at the end and doing adjustments in front in log space. I'm usually converting to linear but am more and more coming back to log as well!
 
Matt Turner said:
So for this style of shooting are you talking about 100 IRE for your highlights? Not some other adjusted level?
Click to expand...

I would imagine he means don't clip the highlights at the point where the C100 clips, which is the top of the waveform (110 or 120 IRE). As long as it doesn't clip, you can bring them back down in post and retain some detail. Mind you, sometimes it is impossible to expose skin at 50-65 IRE and NOT clip highlights, depending on what you're pointing your camera at. In that case, I just decide how much I want to clip the highlights vs. how low I want to go on the skin tones.

Shane is a professional motion picture cinematographer with a budget and lots of lights and a crew who will usually have complete control over how bright a person's skin is vs. the brightness of the highlights in any given shot. But your average C100 operator might not have that luxury. I rarely do.
 
Last edited:
You must log in or register to reply here.
Back
Top