C100: WDR or Canon Log

P

Policar

Carbonite Member
C100 is A cam no need for maximum grading latitude (always shoot Canon Log to a Ninja when intercutting with other systems), more concerned with tonality and detail in low light 3200-6400 ISO.

What settings are best? Shooting without Ninja… too much work to use it lol plus this is just for tv no theatrical. :)

Issue is mid tone tonality needs to be nice and don't want too much macro blocking and really hate the way highlights over saturate with this camera, would rather mitigate that as we will be blowing out a lot of practical sources. (Shooting primarily available light.)
 
What to use can be largely determined by what you shoot.

For weddings I would say WDR.
C-log does require a little more time to get your exposure right, even with exposure simulation on it isn't quite there. Time you don't have in weddings and other live events. WDR is pretty much C-log but pre-graded. All you need to do in post is apply you own colour grade or corrections. From the white papers canon provide they both give you the same number of stops latitude.

WDR also has the added benefit of not having to have your ISO at 850 or higher for maximum latitude. All the documentation says that this only applies to c-log. WDR appears to have the maximum dynamic range at all ISO levels. http://downloads.canon.com/CDLC/Canon-Log_Transfer_Characteristic_6-20-2012.pdf
 
Another fan of WDR, except when lighting conditions get very difficult - then I'll go for C-log.

In bright shiny conditions, sun after rain, golden hour stuff - and funnily enough, probably outdoor wedding 'beauty' shots, I'd be going for C-Log simply because you're getting much more in your highlights. But note well that you really need to ensure you're using V-Assist mode, as by overexposing C-Log, you're kinda negating its benefits and lifting blacks up which will need to be 'tamped down' in post which doesn't always bode well for image quality.

WDR has some sharpening built in, so you may want to make a few variations with less sharpening and NO sharpening (essential for chromakey, BTW). Also, I'm using WDR in studio conditions where I have control over lighting.

Some people seem to have issues with the actual colour of reds with WDR, I've not experienced this problem on the C100 (sigh, C300 different story but there was a software update that sort of fixed this). We all know the issues with reds when using the AVCHD codec - Sikh wedding videographers, watch out.

Policar - Ninja isn't just for TV people. Having bought the Ninja Blade, and notwithstanding its current little problem with pulldown removal, it's become an essential shooting aid for me as the screen is far FAR better than the flip out LCD panel, and whilst the recording codec won't have much impact on talking heads and even most B-Roll, it's great to have a backup, even if you delete it once your AVCHD is safe and ingested.

FWIW, the Ninja Blade has its own 'V-Assist' mode for C-Log shooting, so you can light 'visually' and won't accidentally overexpose.
 
MattDavis said:
FWIW, the Ninja Blade has its own 'V-Assist' mode for C-Log shooting, so you can light 'visually' and won't accidentally overexpose.
Click to expand...

Have you used that yet, Matt?

Would you still use a regular zebra, circa 70%, for caucasian flesh tones with C-Log?

Ben.
 
TBH, no - all 'paid for' shooting and recent tests with the Dual Pixel AF have been with WDR rather than C-Log. Every time it's been sunny enough to give C-Log a good working over, I've been buried deep in some windowless subterranian convention centre. When I emerge, it's into the usual UK 'living inside a tupperware sandwich box', which C-Log seems to hate.

OOooh, and caucasian skin tone is probably more like 65 than 70. LOL - had lovely chats with Andy Bell and Jonathan Harrison about this - the gradual creeping up of IRE levels. I think it's got to do with more people working to computer screen and web delivery.

When Rick Young did the amazing Cinema event, it was startling. As a judge, I'd been viewing entries via Vimeo. I'd made notes on the brightness and gamma, and took to watching them on my Grade 2 Vutrix monitor in a darkened room. But the biggie was to see it projected in the 'perfect' conditions of a proper digital cinema (in this case, the Prince Charles on Leicester Square). The 'webby' ones really did run 'hot' and it didn't really make for great skin tonality. The slightly darker ones seemed far more comfortable.

Now, I do try and poke Canon with a spoon about the fact that their zebras only go down to 70 - and that's where the HIGHLIGHT of skin tone should be placed - so again, the Ninja corrects this oversight by using Zebras down to 50% which caters for a wider range of skin tone. But I'm sure there are fans of using a white/grey card where you plop your 95% zebras on the white card which is why Canon haven't bothered with anything below 70%. But hey, would it have cost so much more to go down to 50?

But one more point: C-Log stuff comes out darker than WDR stuff for a reason. So, 70% skin on C-Log is wa-a-ay over exposed.

Like 'super flat' shooting styles, the 'Expose To The Right' (ETTR) idea of pinning your highlights to just under the clip point can lead to grubbier darks (pulling the mid-greys down to where they should be, stretching the 8 bit tonality out so it becomes equivalent to 7 or even 6 bit LOL). ETTR is more for higher bit depth photography, and 'flatness' is more of the preserve of 10 bit video systems and above IMHO.
 
MattDavis said:
TBH, no - all 'paid for' shooting and recent tests with the Dual Pixel AF have been with WDR rather than C-Log.
Click to expand...

Same here - WDR works enough of the time for me not to have ventured out of it's comfort zone. I like the idea of playing with C-Log, though.

MattDavis said:
OOooh, and caucasian skin tone is probably more like 65 than 70 LOL - had lovely chats with Andy Bell and Jonathan Harrison about this - the gradual creeping up of IRE levels. I think it's got to do with more people working to computer screen and web delivery.
Click to expand...

I personally use the 70% zebra as my "max" highlight allowance. So, if I'm filming a balding badass (like me.. ahem), I'm only just letting the shiny highlight on their head, or cheekbones perhaps, activate the 70% zebra. So far, in a year and 40-odd films with the C100, it hasn't let me down.

This was one of my principle beefs with the AF101 - it was an absolute bastard with highlights and it was often hit and miss - blown-out highlights vs muddy midrange if you you were over cautious and underexposed.

MattDavis said:
But one more point: C-Log stuff comes out darker than WDR stuff for a reason. So, 70% skin on C-Log is wa-a-ay over exposed.

Like 'super flat' shooting styles, the 'Expose To The Right' (ETTR) idea of pinning your highlights to just under the clip point can lead to grubbier darks (pulling the mid-greys down to where they should be, stretching the 8 bit tonality out so it becomes equivalent to 7 or even 6 bit LOL). ETTR is more for higher bit depth photography, and 'flatness' is more of the preserve of 10 bit video systems and above IMHO.
Click to expand...

So, how would you expose fleshtones on a bright sunny day with C Log and your Ninja activated in C Log LUT viewing mode?

Cheers,

Ben.
 
bengiles said:
how would you expose fleshtones on a bright sunny day with C Log and your Ninja activated in C Log LUT viewing mode?
Click to expand...

Well, because the C100 and C300 have an idiotic crapola approach to White Balancing (you need to fill the frame, with no stray non-white things), I take a big lastolite grey/white thing, so I take exposure from the white side (95% trick) and colour balance to the grey side. From there, with V. Assist, I eyeball the result.

I'll be testing in the back garden again when it's sunny and I can grab my son for an afternoon, just to work out what the best C-log WFM looks like.
 
MattDavis said:
I'll be testing in the back garden again when it's sunny and I can grab my son for an afternoon, just to work out what the best C-log WFM looks like.
Click to expand...

Groovy - an IRE figure for max skintone highlights in C Log would be proper useful.

Cheers,

Ben.
 
As a starting point for my own tests, I'll be taking on board Brian Weed's advice of roughly taking 20 IRE points off, but I'll start at 10IRE points lower, then keep going in 5 IRE steps.

Hence 50% zebras would, maybe, sorta, kinda be the equivalent of 70%. So perhaps we should be petitioning for even less.

And then again, how do zebras work out on the Ninja when using the C-Log LUT? LOL - this is why we have to do back garden tests.


Edit: BTW - have you played with false colour as a potential alternative to zebras? When I was shooting with the FS100/700 using my Zacuto EVF and when using the Pix 220, I was pretty happy with it as a quick way of following exposure in changing light conditions and also liked the SmallHD AC7 implementation. I've briefly played with the Ninja Blade false colour and found it a little more 'truculent' and not so quite as pleasant, but maybe slightly modified LUTs can be introduced.
 
Last edited:
Looks like we're doing WDR then, cool.

We own a Ninja 2, but it doesn't seem worth the trouble on a fast-moving shoot. Likely to use it as a wireless monitor and not record to it. Client didn't specify any format, just prores of final edit delivery so whatever.

Is there actually more highlight detail with C LOG? I have pointed the camera at a just <109 IRE object and it reads just <109 in either mode… Seems like they have the same clip point even if the curve is different.

Conversely, SLOG 2 has 1.5 stops better DR than rec709 from the F5 but I believe it's because the camera pushes from 800 ISO to 2000 ISO with digital not analogue gain, hence muddy shadows in the F5. (Nice camera overall, though!) But you rate WDR and Canon Log both at 850 ISO.

I will try out lower ISOs see if WDR clips differently (maybe Canon is doing something similar to the F5 or highlight tone priority in log mode only) but I expect 850 ISO is native point for maximum highlight detail on either. Need to check…. We need highlight detail here. Normally I meter religiously but light levels are so low (3200ISO f2, maybe) that my meter might not give me much useful info. We are shooting available light night exteriors in city.

Would never put skin tones at 70 IRE in log… 35-40 IRE in rec709 feels like middle gray to me, maybe 32 IRE or lower in log. Skin tones being a stop brighter I'd put them at 40 IRE, but I don't know. Usually just meter and ignore the waveform. Lazy lol.
 
I seem to go back and forth between the two often, but stick on Cinema more often. I like to color my footage myself and it really lets you play with the image.
An external monitor is a must for me at least when using Cinema, because the built in viewfinder shows properly exposed footage very dark. I try to keep my reflected whites at 70 IRE, and it seems to work well for me.
 
Is there actually more DR in Canon Log or is it just flat so it's more flexible to grade (eg better tonality if you totally screw up exposure)? Highlights appear no different, maybe tonality in shadows? Any difference in noise?

Might just go with Log because it's familiar. Won't have the luxury of an external monitor most of the time, though, unless the client shows up and wants to watch.
 
Log reaches one more stop up and down if it's there to be captured. Otherwise you're just squishing your tonal range in a fragile 8 bit environment.

If you use C-Log on the wrong shot, it can look worse than using a more gentle Custom Picture.

WDR is like CineGamma 3 on Sonys, it's based on Rec709 but adds bells and whistles in packing those last few stops of highlight details.

C-Log is a whole new process and works great in very difficult situations, but shouldn't be a 'lowest common denominator'. If you're used to lighting for video, C-Log will bite you on your bum. Use a Rec709 style Custom Picture profile - or, heck, WDR FFS. :)

Remember, log is not raw. Log redistributes the tonal range over the digital scale in a non-standard way, so you're going to have to 're-pack' them in post. C-Log is 8 bit, and you really need to maximise your utilisation of those puny 220 levels of grey per channel. Your WFM needs to be 'packed out' and your blacks need to be below 25 IRE on your WFM so you can get all that highlight detail, or you're heading to tears before bedtime.
 
MattDavis said:
Log reaches one more stop up and down if it's there to be captured. Otherwise you're just squishing your tonal range in a fragile 8 bit environment.

If you use C-Log on the wrong shot, it can look worse than using a more gentle Custom Picture.

WDR is like CineGamma 3 on Sonys, it's based on Rec709 but adds bells and whistles in packing those last few stops of highlight details.

C-Log is a whole new process and works great in very difficult situations, but shouldn't be a 'lowest common denominator'. If you're used to lighting for video, C-Log will bite you on your bum. Use a Rec709 style Custom Picture profile - or, heck, WDR FFS. :)

Remember, log is not raw. Log redistributes the tonal range over the digital scale in a non-standard way, so you're going to have to 're-pack' them in post. C-Log is 8 bit, and you really need to maximise your utilisation of those puny 220 levels of grey per channel. Your WFM needs to be 'packed out' and your blacks need to be below 25 IRE on your WFM so you can get all that highlight detail, or you're heading to tears before bedtime.
Click to expand...

I'm trying to find that extra stop of highlight detail in Canon Log and can't find it. Clip point seems to be the same with both.

We're just shooting available light at night so super high contrast, super low light, trying to get the most tonality possible without having to use an external recorder.
 
Policar said:
Is there actually more DR in Canon Log or is it just flat so it's more flexible to grade (eg better tonality if you totally screw up exposure)? Highlights appear no different, maybe tonality in shadows? Any difference in noise?

Might just go with Log because it's familiar. Won't have the luxury of an external monitor most of the time, though, unless the client shows up and wants to watch.
Click to expand...

There's no more DR in Log. Log has a more gradual highlight rolloff, more noise, it's harder to expose properly, always looks off on the LCD. I use Wide DR. The big drawback to Wide DR seems to be color accuracy, but manipulating the picture profile can compensate for this.
 
About DR canon-log vs. WDR gamma - the default DR for C100 at 0dB gain (640ISO) is 12 stops. The canon-log has a greater DR in this setup than WDR gamma. Why?

If you set up gain -6dB (320ISO) then you'll get a little pressed black level and you will have a little more space at highlights with WDR. But this pressed black is a problem at evening, middles and black are in lower level (you will get darker images at middles and less detail in compressed highlights, it is really visible).

Canon-log at 0db gain (640ISO) or at +2.5dB (850ISO) has better black, middles are also at lower level (you must correct this a very carefully at postproduction because there is a 8 bit limit) and highlights have more resolution at details (highlights are less compressed than with wdr gamma). With canon-log you get the better gradation, every one stop has exactly the same amounts of shades and gamma curve is smooth. But 8bit limit may be more visible if you need to more lift up the middles. Also one color gradients show this 8bit limit and you often will see a banding. After color correction of the canon-log you will often get the similary result as WDR gamma but with the better accuracy.

You must learn these differences between WDR and canon-log gamma, try the wdr and canon-log gamma curves in various situations. I like to canon-log with a little higher exposure as some compromise between the 8bit limit and nice smooth gradation. But if the picture has a lot of bright places then could be better to do the correct exposure at lower level with canon-log gamma.

But yes, wdr at -6dB (320ISO) has the same white clipping as canon-log at +2.5dB (850ISO), if you have the same exposure of the CMOS chip, the main differences you will see at a gradation. And canon-log + color corrections get often a very similar result as wdr gamma (but wdr is a little desaturated at highlights, I don't like this on the human face).
 
Last edited:
Pave1 said:
About DR canon-log vs. WDR gamma - the default DR for C100 at 0dB gain (640ISO) is 12 stops. The canon-log has a greater DR in this setup than WDR gamma. Why?

If you set up gain -6dB (320ISO) then you'll get a little pressed black level and you will have a little more space at highlights with WDR. But this pressed black is a problem at evening, middles and black are in lower level (you will get darker images at middles and less detail in compressed highlights, it is really visible).

Canon-log at 0db gain (640ISO) or at +2.5dB (850ISO) has better black, middles are also at lower level (you must correct this a very carefully at postproduction because there is a 8 bit limit) and highlights have more resolution at details (highlights are less compressed than with wdr gamma). With canon-log you get the better gradation, every one stop has exactly the same amounts of shades and gamma curve is smooth. But 8bit limit may be more visible if you need to more lift up the middles. Also one color gradients show this 8bit limit and you often will see a banding. After color correction of the canon-log you will often get the similary result as WDR gamma but with the better accuracy.

You must learn these differences between WDR and canon-log gamma, try the wdr and canon-log gamma curves in various situations. I like to canon-log with a little higher exposure as some compromise between the 8bit limit and nice smooth gradation. But if the picture has a lot of bright places then could be better to do the correct exposure at lower level with canon-log gamma.

But yes, wdr at -6dB (320ISO) has the same white clipping as canon-log at +2.5dB (850ISO), if you have the same exposure of the CMOS chip, the main differences you will see at a gradation. And canon-log + color corrections get often a very similar result as wdr gamma (but wdr is a little desaturated at highlights, I don't like this on the human face).
Click to expand...


Way over my head, but thank you for the detailed explanation. Will revisit it.

Ended up shooting Canon Log to a Ninja when possible (80% of the time) then to SD card when we were cramped. Nothing below 2000 ISO.

Why does WDR at 320ISO clip the same as log at 850ISO? What about 850 vs 850?
 
With C-Log, you expose reflected whites at 70%, therefore 30 units of highlight protection. Wide DR puts reflected whites at 80% or 20 units of highlight protection, assuming 18% gray card exposed at 40% for both. REC709(Norm gamma)would be more like 90-95% whites, offering little highlight protection.

C-Log has more tonality in highlights than WDR, flesh should not be higher than 50%, or there will be loss of tonality in the skin tone due to compression in the mids.
 
You must log in or register to reply here.
Back
Top