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Shooting an old train on Green screen
Hello everyone,
In a couple of weeks I’m going to shoot a short film in an old train cabin. of course we are shooting in a stand still train, and using green screen for the outside.
however before I go any further, I’d like to consult with you about preparing for this shoot.
The director really likes the dirty windows of the train, as seen here.
Now the window already has some ND cover on it, and the dirt does alter the real colors of the outside. Should we clean the windows and add this dirt back in after effects later? or will it be ok to shoot this way.
other than this, it’s a night ride and a night shoot, and the director really wants reflections. now I’ve never dealt with reflections and green screen before. how much of a problem is that? I know it’s impossible to fake such reflections in after effects.
Thanks for the answers ☺
Eli
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15 Replies
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It is perfectly possible to pick up nice reflections and dirt with a good keyer from well shot footage.
But the issue that so many people are running up against these days is that they are shooting highly compressed formats and then wondering why they can’t get subtle detail into their keys without horrible amounts of noise creeping in and ruining the whole thing. Reflections need very clean source footage to key properly.
So the most important question you need to be asking is how much noise you are going to get off the camera.
Looking at the combined RGB output is not going to give you a good picture because you’re not seeing the true horror of what’s underneath. Keyers need nice clean signals in all three channels and this is where the compression artefacts really kill you. Make sure to run some camera tests where you analyse each channel for noise. If you see blocky artefacts, your key is dead in the water before you start. If one channel is noticeably noisy, you are entering a world of pain.
Simon Ubsdell
tokyo productions
hawaiki -
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It’s a nice tutorial as always from Andrew Kramer, but the important thing to notice about it is that it requires a very, very render-intensive denoise process to be able to handle the reflections in this scene. (And that’s just a tiny clip not a whole film.)
And this is for the reasons that I gave in my post above. Compressed footage is always going to create horrendous problems for subtle keying effects like reflections.
Simon Ubsdell
tokyo productions
hawaiki -
Thanks for the quick replies everyone
We will be shooting with a mini Alexa – Log C. So Noise shouldn’t be much of an issue, or am I wrong?
https://www.youtube.com/elireo
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[Dave LaRonde] “People these days think, “Oh, it’s 4K footage! Our troubles are over!””
I couldn’t agree more.
4K is the work of the devil and the compression issues are simply not understood by the majority of people shooting it.
As a keyer developer myself, I have seen some real horror stories from users who haven’t realised what they were getting into until it was too late.
I blame the ridiculous marketing that has completely white-washed this issue.
Simon Ubsdell
tokyo productions
hawaiki -
Ok so after checking with the Director of photography it’s going to be
Pro-res 444 – 2K – Log C.https://www.youtube.com/elireo
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The other thing I would say about this video is that it shows very clearly how unsuited Ae is to even slightly complex compositing situations.
You are far better off working in Nuke or Fusion if you’re doing anything except the simplest key.
Getting great looking keys is all about being able to have total control over how the comp fits together, especially in terms of splitting off processes to deal with particular issues of particular areas of the frame. All of this is still doable in Ae, but it’s a real pain and seriously clunky. And the clunkiness means a lot of the time you are not going to push for perfection because it’s just too much work.
Simon Ubsdell
tokyo productions
hawaiki -
I don’t know enough about the Alexa Mini to say for sure, but that sounds as though it should give decent enough results if it’s identical to its big brothers.
Don’t forget that ProRes (even 4444) is a compressed codec so it’s not without issues of its own.
I cannot stress too strongly the importance of running tests and looking with an extremely critical eye at the cleanness of each channel.
Also bear in mind that an underexposed green screen is going to be a lot noisier than a well lit one, but your director might be wanting a subdued look which is going to fight with that. There are plenty of complex and not necessarily easily resolved factors you need to take into consideration here.
Simon Ubsdell
tokyo productions
hawaiki -
Well I’ve been working with after effects for the past 7 years and never really used fusion or nuke.
How hard of a transition is it?https://www.youtube.com/elireo
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[Dave LaRonde] “You might be successful shooting this as a practical effect, with a mechanism moving various lights against a black backdrop. “
Check out how they mixed green screen and practicality for Girl on The Train (last paragraph):
https://www.studiodaily.com/2016/10/studiodaily-dossier-the-girl-on-the-train/Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn]
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