7D 8-bit video--better to leave contrast alone?

[Bill Binder]

One aspect of this conversation which hasn't been (explicitly) mentioned is the fact that whatever is being done in-camera is being done with more bits than you have in post (even if you move to a more robust intermediate for post work). So, there may in fact be some advantages to getting things "more right" in camera than in post. Of course, you'll always be doing both, but you get my point...

[Declan Smith]

I have followed the general advice to use a flat response (actually the superflat preset) to give more options later in post. However, what I have found is that a number of clips have caused alot of grief, particularly skies where there is gradation between various shades of grey.

For example, I shot some clouds with the view to making them look stormy. So in post I increased the contrast. This left really unacceptable banding or posterization. Through trial and error I have found the best way to minimise this effect in post is to add the contrast at the point of conversion between h.264 and prores. Having said that I still need to process the clip with de-noise of smoothing plugins to make it acceptable.

I am now not entirely convinced that the picture style should be flat, but feel that the settings should be set as closely as possible to the desired final result, at least with regards to contrast. In hindsight, I should have adjusted the picture in camera to look how I wanted it.

I know the clips will still need to be graded in post, but is the best approach to avoid this type af artifact ?

[Jon Fairhurst]

The banding you are getting is as likely due to 8-bit processing as 8-bit content. I don't know if FCP has a 16-bit per color or 32-bit float mode, but if it does, give it a try. When I grade in Vegas in 8-bits, I get bands. When I grade in Vegas or AE in 32-bits, things are much smoother.

Another trick is to apply a light amount of noise reduction as a first step - in 32-bit 4:4:4 or 4:2:2, if possible. That will generate intermediate values. Do your grading next and only convert back to 10 or 8 bits at the very end - preferably with some dither or gentle noise added at the end.

I'm convinced that many people have condemned 8-bit capture over the years when the big problem is the combination of 8-bit capture and 8-bit processing. 8-bit capture isn't ideal, but when handled ideally, the results can be surprisingly good.

[Declan Smith]

I have done some very very quick and dirty tests (not very scientific as I am not an expert on this field), but basically pointed the camera at some clouds under various settings / picture styles. Then I took this clips into FCP, added a brightness/contrast, whacked up the contrast to 70% and added a three way CC and boosted the midtones towards orange and the highlights towards blue (just to add some CC processing).
The clouds had a mass of graduated grey then a break underneath with bright sky.

The took clips of:

superflat - normal exposure - CRAP - loads of banding/posterization
superflat - under exposed - Better, but with slight posterization in the flat clouds
neutral - low contrast, normal exposure - More contrasty look, very slight posterization
neutral - low contrast, under exposed - Looks fine (but then it's a bits too dark)
neutral - max contrast normal exposure - Looks a bit over exposed in the highlights but clean
neutral - max contrast under exposed - Looks good and clean.

I then pushed the contrast up to 100 and observed the histogram in the scopes. The best setup (i.e. with virtually no gaps) was:

neutral - max contrast, underexposed

As I said, not exactly scientific, but I now would probably not use superflat at all now, and would change the picture style settings for neutral depending on what I was shooting and try and get the contrast as near to the final desired result, but allowing a little room in post.

In fact, I went over (at random) some clips I have that had this posterization / banding issue, and used exiftool to look at all the settings, and every clip I had an issue with used the superflat style.