Its been a busy weekend on this commercial. I've uploaded a few clips that we shot with the C 300. I had the opportunity to test the new Canon C300 first in Canada. Most of the testimonial based commercial was shot on the Sony F3, but we decided to shoot some of the b roll with the C 300, then on our last day we jumped in and shot the final 2 interviews with the C 300. We used Canon 16 -35L 2.8, 24-70L 2.8, 70-200L 2.8, and a Zeiss 85mm ZF 1.4 with a Nikon to EF adapter for one of the interviews. Mostly at iso 850, with one at iso 1000, in Canon log 4:2:2 50mb to CF cards.

Canon C300 selects for commercial on Vimeo

Very nice.....especially with the windows behind, it shows how well it handles the range.

Jim Martin
Filmtools.com

I agree. I really like the look.

2 questions:

1) How much grading was done in post?

2) Do you have F3 footage in similar setting from the commercial that we can compare?

Thanks.

Most of the testimonial based commercial was shot on the Sony F3, but we decided to shoot some of the b roll with the C 300, then on our last day we jumped in and shot the final 2 interviews with the C 300.

Canon C300 selects for commercial on Vimeo (http://vimeo.com/32763902)

Nice stuff, Nigel.

Just so we know what we're looking at, is this essentially the c-log rendering or has it been graded at all. Also, do you care to comment on your impressions versus the F3?

Barry

I agree. I really like the look.

2 questions:

1) How much grading was done in post?

2) Do you have F3 footage in similar setting from the commercial that we can compare?

Thanks.

This is the straight Canon Log footage, brought into FCP 7 through log and transfer at Pro Res. I think I only did it at LT. The Canon Log seems to have more colour information in it than the F3's S log. Its a lot flatter. The interviews were on the F3, and b roll with the C 300

Nice stuff, Nigel.

Just so we know what we're looking at, is this essentially the c-log rendering or has it been graded at all. Also, do you care to comment on your impressions versus the F3?

Barry

Barry

It was a nice combination to use both cameras. I had my F3 built in a full tripod configuration. I kept the C 300 stripped down for quick b roll. We were not going to even use the C 300, but the director asked if we could to move a little quicker. The camera worked without any problems at all. That's why we tried it on our final two interviews. It is the Canon log footage from the camera, with no grading. I used each camera with the same lighting set ups. Just matched ISO's. Didn't have time to test beforehand to see where each camera rated. Just went of the ISO's in the camera, and there was no drastic difference in how I had to expose.

I think there will be a lot of comparisons between both cameras. Each having a little something that the other doesn't. I like the idea of using them both in different scenarios. This was one that I thought of where I would use a 5D in the past. I had much better options with the C300 with the EF mount on this one.

This is the straight Canon Log footage, brought into FCP 7 through log and transfer at Pro Res. I think I only did it at LT. The Canon Log seems to have more colour information in it than the F3's S log. Its a lot flatter. The interviews were on the F3, and b roll with the C 300

Thank you Nigel. Just to make sure I have this correct: on the video you posted, the interviews were F3 and b roll was C300?

Thank you again for posting this.

Thank you Nigel. Just to make sure I have this correct: on the video you posted, the interviews were F3 and b roll was C300?

Thank you again for posting this.

Sorry for any confusion. The video I posted was all Canon log footage from the C 300, including the those two interviews. The other elements (which I did not post) were shot with the F3.

N

Sorry for any confusion. The video I posted was all Canon log footage from the C 300, including the those two interviews. The other elements (which I did not post) were shot with the F3.

N

Ah thanks. Do you have any of the Sony footage that you can show?

Barry

It is the Canon log footage from the camera, with no grading.

One of the comments that stuck from the talkbacks at the canon launch event was when Vincent Laforet mentioned that c-log was quite pleasant to view ungraded compared to s-log. I looked at your S-log test /Paris video and I think that statement is born out. Obviously two different subjects, but the c-log seems to be closer to a normal color level so it's not as shocking (when you view s-log it's hard to imagine where the color is going to come from in the final grade.

I guess the question is does this in anyway make the footage less gradeable. It would be great to see graded samples of both cameras should the opportunity arise.

Again...thanks for the post.

We definitely have seen that. The F3 in S log is a lot flatter than the Canon log. I spoke with Vincent at the launch, and he talked about that. I've noticed that this weekend. The colours are very natural. Here's my low light cake test.
Canon C 300 The Cake Test on Vimeo

Thanks for posting.

It seems c-log is more designed to show high contrast scenes attractively, as opposed to holding highlight detail for future grading.

The best way to optimize your video content is to think about the user and who you want to engage with your video.

First let me say that as yet I have not used C-Log in anger, only seen it at a couple of hands on demo events and in downloaded clips.

From what I've seen C-Log and S-Log are two quite different things. S-Log on the F3 is a true Log curve where each stop of exposure is recorded using roughly the same amount of data and the available dynamic range is about 13.5 stops. It is inevitable that when you use a true log curve like this and play it back on an uncorrected Rec-709 (standard HD gamma) monitor that it will look very flat and very washed out. This is a result of the extreme gamma miss-match across the entire recording range. If you had a monitor that could display 13.5 stops (most only manage 7) and the monitor had a built in Log curve then the pictures would look normal.

What has too be considered is that S-Log is designed to be used with 10 bit recording where each stop gets roughly 70 data bits ( this roughly means 70 shades of grey for each stop).

Now lets consider the Canon C300. It has no 10 bit out, it's only 8 bit. Assuming Canon's sensor can handle 13.5 stops then using 8 bit would result in only 17 bits per stop and this really is not sufficient, especially for critical areas of the image like faces and skin tones. A standard gamma, without knee, like Rec-709 will typically have a 7 stop range, this is a deliberate design decision as this yields around 34 bits per stop. As we know already if you try to do a hard grade on 8 bit material you can run in to issues with banding, posterisation and stair stepping, so reducing the bits per stop still further (for example by cramming 13.5 stops into 8 bits) is not really desirable as while it can improve dynamic range, it will introduce a whole host of other issues.

Now for some years camera sensors have been able to exceed 7 stops of dynamic range. To get around the gamma limitation of 7 stops, most good quality cameras use something called the knee. The knee takes the top 15 to 20% of the recording range to record as much as 4 to 5 stops of highlights. So in the first 0 to 80% range you have 6 stops, plus another 4 to 5 stops in the last 20%, so the overall dynamic range of the camera will be 10 to 11 stops.

How can this work and still look natural? Well our own visual system is tuned to concentrate on the mid range, faces, foliage etc and to a large degree highlights are ignored. So recording in this way, compressing the highlights mimics they way we see the world, so doesn't actually look terribly un-natural. OK, OK, I can hear you all screaming... yes it is un-natural, it looks like video! It looks like video because the knee is either on or off, the image is either compressed very heavily or not at all, there is no middle ground. It's also hard to grade as mid tones and highlights have different amounts of squashing which can lead to some strange results.

So the knee is a step forward. It does work quite well for many applications as it preserves those 34 bits of data for the all important mid tones and as a result the pictures look normal, yet gives a reasonable amount of over exposure performance. Next came things like cine gammas and film style gammas.

These often share a very similar gamma curve to standard gammas for the first 60-70% of the recording range, so faces, skin, flora and fauna still have plenty of data allocated to them. Above 70% the image becomes compressed, but instead of the sudden onset of compression as with a knee, the compression starts very gently and gradually increases more and more until by the time you get close to 100% the compression is very strong indeed. This tends to look a lot more natural than gamma + knee, yet can still cope with a good over exposure range, but depending on the scene it can start to look a little flat as your overall captured range is biased towards highlights, so your captured image contains more bright range than low range so will possibly (but not always) look very slightly washed out. In my opinion, if shooting with cinegammas or similar you should really be grading your material for the best results.

Anyway, back to the Canon C300. From what I can tell, C-Log is an extension of the cinegamma type of gamma curve. It appears to have more in common with cinegammas than true S-log. It looks like the compression starts at around 60% and that there is a little more gain at the bottom of the curve to lift shadows a little. This earlier start to the compression will allow for a greater dynamic range but will mean fewer bits of data for skin tones etc. The raised lower end gain means you can afford to underexpose more if you need to. As the curve is not a full log curve it will look a lot more agreeable than S-Log on an uncorrected monitor, especially as the crucial mid tone area is largely unaffected by strong compression and thus a large gamma miss-match.

For the C300 this curve makes complete sense. It looks like a good match for the cameras 8 bit recording giving a decent dynamic range improvement, largely through highlight compression (spread over more recording range than a conventional knee or cinegamma), keeping mid tones reasonably intact and a little bit of shadow lift. Keeping the mid range fairly "normal" is a wise move that will still give good grading latitude without posterisation issues on mid range natural textures.

there is a little more gain at the bottom of the curve to lift shadows a little.

Great post Alister!

Paul Steinberg in this video http://www.dvinfo.net/forum/new-canon-cinema-eos-c300-c300-pl-cameras/504039-paul-steinbergs-c300-demo.html figured that there is more noise when shooting a low light scene with a lower ISO setting then when shooting the same scene with a little higher ISO. Do you think that this is because of the gain that is being applied to the lower end of the curve?

@Nigel: did you encounter such a thing when doing your lowlight test? Judging from your posted video the image looks noisier at the higher ISO...

Well now Canon have posted their white papers, I've been able to look at a graph of the C-Log curve, although all the published charts come with a strong "this is a representation" disclaimer and no real scales, so no idea how accurate they are.

From what I've seen in the white papers the compression starts around 30-40% which was is lower than I had observed. The range is restricted to 12 stops (compared to the F3's 13) which will help the image look more natural compared to s-Log. 12 stops is only half a stop increase over what is typically achieved with a cinegamma or other semi-log gamma, but this still makes a lot of sense with the C300 as trying to squeeze more into 8 bits would in my opinion be a step too far. 12 Stops is a very respectable range.

With a log type curve as the gamma gain decreases (compared to a standard gamma) with brightness there can be a perceived reduction of noise in the mid to high range when you compare standard and log gammas side by side. But I would still expect a higher ISO to produce a noisier image. It may be that when the C300 is locked in to CP Cinema mode that there is a reduction in detail correction and this may reduce the appearance of noise.

Argh..... I'm so eager to get my hands on a C300 to put it through it's paces!

Thanks Alister for the great post! Canon is doing a big event here on Saturday so I'll, as always, fish around and see what I can find out.

Happy New Year!

Jim Martin
Filmtools.com

there can be a perceived reduction of noise in the mid to high range when you compare standard and log gammas side by side.

The noise goes up in the blacks - not the mids or highs...

That's what I am implying. Is that when you compare Log and standard gamma there may appear to be more noise in the blacks with a standard gamma than log for the same exposure as there is less gain and thus noise in the mid and high range with log.

Remember that if you have a higher dynamic range, you can open the iris up more before you over expose so your whole shot, including the mid range is also exposed brighter and the whole shot will look brighter. OR you can open the iris up a bit more but can use less gain and as a result the noise looks reduced as as well.

That's the theory at least... I will hopefully be able to confirm all this once my C300 is delivered.