Best Settings to Shoot Green Screen

[Mike Panganiban]

Hey all, have an upcoming green screen shoot that will try to simulate a couple different lighting looks (on subject), anyone have some tips on how to achieve the best key? A previous GS project was a little on the grainy side so I'm trying to avoid that.

Much appreciated!

 

[Michael Tiemann]

I've been doing some GS testing for an upcoming shot and am pretty pleased with the results I'm getting. I'm using UltiMatte in Premiere Pro and lightly playing with the Default settings.

First, I have the talent 10-12' in front of the GS.

Second, because it's a talking head, I have a GS that is not too wide. By having the GS extend as little as possible to one side or the other, the sides of the subject are not awash in green light as they would be if the GS were 40' wide.

Third, I'm lighting the GS 1-2 stops less than the face of the talent. (I don't have the files with me right now, so I cannot verify that precisely). This further minimizes spill.

Finally, and as per usual, I've learned to never starve the sensor when it comes to lighting the main talent. I used to chronically underexpose my images when I used ISO 1280 and even ISO 800 as my baseline. So I switched to ISO 320, which gave me great images when developed at ISO 800. After a while I learned to read my histogram and other tools well enough that I can shoot at ISO 800 and post at ISO 800. If your grain was in the talent, not in the GS, then you've underexposed the talent! If your grain was in the GS, you underexposed your GS, a lot!

 

[Christoffer Glans]

I choose to expose with RAW or low ISO and keep my compression to the minimum possible and always at the highest resolution. I then do all the keying after I debayered and downscaled to my working resolution, if I want to finish in 4K but still work with some resolution I downscale down to 5K or 4,5K and do the keying there to try and maximize the color quality.

 

[Randall Weatherington]

Do yourself a really big favor and put green light on the green screen. These days, it can easily be done with green LEDs.
During my career doing blue and green screen shots, one always wants to avoid white light contamination on the screen whenever possible.
For film, we also lit the screen 1/2 stop hotter than the foreground.

 

[Brendan H. Banks]

A lot of really great tips here. Also, just something I experienced when I was first doing a good bit of GS -- your VFX/compositor/editor will most likely do a garbage matte around the talent so making sure the key is bright and even behind them and any "action area" is very important. The edges of the frame are less-so. I would waste valuable time filling out the corners only to be told later that they didn't really need that so much. You'll notice this same thing on very large budget features if you check out some BTS photos.

Obviously do your best, but if your kit is limited, definitely make sure to hit the area around the talent the most.

All the other tips above are great, especially about separation from the background so you don't get any green reflected light onto your talent.

 

[Mike Panganiban]

Thanks for the tips so far everyone. Is it safe to say that shooting 320 ISO is most advisable?

 

[Michael Tiemann]

Thanks for the tips so far everyone. Is it safe to say that shooting 320 ISO is most advisable?

Shooting at ISO 320, until you get all the other kinks out, will go a long way toward addressing the single most common problem that REDUSERs have, which is chronically underexposing their images. Once you get used to really hitting the sensor with light, and how great those images can be, you can start to tighten up your settings to balance your settings (and lighting) to your scene.

 

[David Battistella]

You can also use a great app called GREENSCREENER, to measure how even your lighting is. I just did a big series of tests with blue and green screen and I felt like blue screen, lit tungsten was giving the best results, warmer light on the green screen was also a bit better. Also, ISO 400 and one stop over key works but it is best to test with the shot you are trying to end up with.

David

 

[Björn Benckert]

For green screen high exposure is key. so low iso and highlights right under clip and lot of fill light and rather pull contrast in post. Noise and unbalanced light are the evil onces. Better color balance in front of lens to 5600K than pulling kelvins around in camera as that simply gives you a cleaner image.