ADOBE PREMIERE PRO: Tutorials Forum Articles Podcasts Basics Forum Creative Cloud Debate

When shooting for Green Screen...

COW Forums : Adobe Premiere Pro

<< PREVIOUS   •   FAQ   •   VIEW ALL   •   PRINT   •   NEXT >>
Duke SwedenWhen shooting for Green Screen...
by on Feb 22, 2016 at 10:08:15 pm
Last Edited By Duke Sweden on Feb 22, 2016 at 11:23:53 pm

If I'm shooting green screen footage, should I shoot in Standard profile rather than a Flat profile, since the dynamic range of the surrounding set is going to be keyed out anyway?

I'm using a DSLR that shoots in h264. Anything other than Standard profile deletes usable color information, or so I've read. So, since I don't need DR in my shadow areas, should I just shoot in Standard?


Return to posts index

Duke SwedenRe: When shooting for Green Screen...
by on Feb 23, 2016 at 5:02:48 pm

And the answer, after MUCH google wording configurations is....shoot flat.


Return to posts index

Alex UdellRe: When shooting for Green Screen...
by on Feb 23, 2016 at 5:32:28 pm

Hi Duke...

I guess...

the theory would be....

why paint yourself into a corner?

Isn't the idea of shooting flat to provide the most latitude in post?

Where as, if you try to shoot with a look, some parts of the range might be captured (clipped) in a way as to be unrecoverable to adjusted to your satisfaction?

Alex Udell
Editing, Motion Graphics, and Visual FX
Let's Connect on Linkedin
Examples: Retail Automotive Motion Graphics Spots
Example: Customer Facing Explainer Video
Example: Infotainment & Package editorial


Return to posts index


Duke SwedenRe: When shooting for Green Screen...
by on Feb 23, 2016 at 6:13:08 pm

Hi Alex. My reasoning, and again I'm just a hack, was that once you've keyed out the clip there's nothing left but the (well lit) body. Now, as an example of why I asked the question, on my latest little clip, I shot using Cineflat, the flattest profile available for Nikon. After keying out the background, when I went to tweak the exposure, brightness, etc. and do some color grading, the background reappeared and I couldn't key it out because it was this really weird dark gray/purple color. Remember, I'm only using a Nikon D5500, h264 compression. Now that I think about it, this really wasn't the place to ask!

But thanks for responding. Cheers!


Return to posts index

Chris WrightRe: When shooting for Green Screen...
by on Feb 23, 2016 at 7:35:38 pm

i've read a lot about this and here comes my 2 cents...
ok, so the trick here is 8 bit vs 10 bit(i.e. professional).

remember the 8 bit log for the GH4? in the beginning, everyone was like,

wow! it's totaly worth it to buy the log thingy, until they found it's 8

bit.


Well guess what, all that pulling and pushing to get back to where you

need to be(with a LUT) doesn't actual help you at all if you're 8 bit. and

h.264 isn't going to help much either, it's a bitrate limited codec.


i.e. if you do want to shoot flat you need a camera with very low noise

and 10 bits and guess what keying likes? yep, low noise.


->What you are actually looking for is a "Neutral Picture Style", not a

flat profile. although this technique is confusingly called prolost flat.

i.e. sharpness 0, contrast 0, saturation(2 notches left)

the reason saturation is not 0, if you throw it away in the camera's
codec, then its almost impossible to get it back in 8bit, 4:2:0.

Cinestyle may give 1-2 more f-stops,but the color noise will go waaaay up.

Another important thing to save your bits from artifacting is to make
doubly sure your white balance is correct, so you're not fighting the temp
colors in post.


Return to posts index

Duke SwedenRe: When shooting for Green Screen...
by on Feb 23, 2016 at 9:09:04 pm

i've read a lot about this and here comes my 2 cents...
ok, so the trick here is 8 bit vs 10 bit(i.e. professional).

remember the 8 bit log for the GH4? in the beginning, everyone was like,

wow! it's totaly worth it to buy the log thingy, until they found it's 8

bit.


Well guess what, all that pulling and pushing to get back to where you

need to be(with a LUT) doesn't actual help you at all if you're 8 bit. and

h.264 isn't going to help much either, it's a bitrate limited codec.

See, that was my original point. I said that using a flat profile removes color information that I can't get back. Hey, I ain't as dumb as I thought I was!


i.e. if you do want to shoot flat you need a camera with very low noise

and 10 bits and guess what keying likes? yep, low noise.

Again, Nikon D5500. h264. Total amateur. Still like to do things right.


->What you are actually looking for is a "Neutral Picture Style", not a

flat profile. although this technique is confusingly called prolost flat.

i.e. sharpness 0, contrast 0, saturation(2 notches left)

the reason saturation is not 0, if you throw it away in the camera's
codec, then its almost impossible to get it back in 8bit, 4:2:0.

Going back to my original point ;-)

Cinestyle may give 1-2 more f-stops,but the color noise will go waaaay up.

I don't usually use Cinestyle. Usually Flaat11 or the D5500's "Flat" profile. I'll try Neutral next time.

Another important thing to save your bits from artifacting is to make
doubly sure your white balance is correct, so you're not fighting the temp
colors in post.

I ALWAYS set my white balance before each shoot, so that's not a problem.
Thanks for your input. Cheers!


Return to posts index


Alex UdellRe: When shooting for Green Screen...
by on Feb 23, 2016 at 10:18:32 pm

Hey Duke...

On your first key pass, if you take a look at your matte and it's good...


you may need to export with alpha....then grade on that...

not sure why adjusting the color post KEY would bring back the backing unless you were tweaking a filter upstream of the key....?


but I have seen some weirdness in Ppro from time to time is GPU is enabled and how it handles (or doesn't) alpha channels.

Alex Udell
Editing, Motion Graphics, and Visual FX
Let's Connect on Linkedin
Examples: Retail Automotive Motion Graphics Spots
Example: Customer Facing Explainer Video
Example: Infotainment & Package editorial


Return to posts index

Duke SwedenRe: When shooting for Green Screen...
by on Feb 23, 2016 at 11:14:53 pm

Yes, Alex that's entirely possible that I added a preset, most likely brightness/contrast before tweaking which caused the background to partially reappear.


Return to posts index

Tero AhlforsRe: When shooting for Green Screen...
by on Feb 23, 2016 at 6:20:39 pm

Depends on the keyer. I've done a bunch of keying on stuff that had been shot/debayered flat from Alexa and Red cameras. I've had no problems with Keylight and Quantel/Flame keyers. But these were real movie productions with proper (or as proper that they could do on their budget) sets.


Return to posts index


Duke SwedenRe: When shooting for Green Screen...
by on Feb 23, 2016 at 7:33:27 pm

Well, there ya go. Mind you I don't have a lot of problems with getting good keys, but I'm not really doing complicated keying or post production grading. In fact I'm too embarrassed to even put up any samples. Anyway, you guys, as usual, have been very helpful.
Thanks!


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2016 CreativeCOW.net All Rights Reserved
[TOP]