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5DM2 and Green Screen

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Kim Huston
5DM2 and Green Screen
on Sep 18, 2009 at 3:17:01 pm

I never considered it until I shot a green screen project with the Canon EOS 5D Mark II camera, but how does one deal with out of focus shots in front of a green screen?

Do you you just avoid it? Make sure everything in front of the screen is in focus and then your only depth of field is between the live action and the green screen footage?

The problem I was having was that on close ups, part of the live person's face was in focus and part was out, as is standard with the 5DM2 DOF style. But it made for tricky keying. It also came up when one character was in the foreground and one was a little bit behind the other.
Maybe the solution is just a really feathered edge? I wasn't sure what to do. Time constraints meant I didn't have any time to play, but I plan to put more time into the keying (and tracking!) and get the edges really solid with no green at all.








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Todd Terry
Re: 5DM2 and Green Screen
on Sep 18, 2009 at 3:33:22 pm

Well I'm a BIG proponent of big-sensor cameras and DoF converters... because I like being able to control DoF and get it shallow when I need it.

But you have just discovered one of the big problems with doing so... when doing blue or greenscreen work and any kind of compositing, the super shallow DoFs can make keying very difficult.

If you encounter a similar situation in the future, your best bet is to try to make the depth of field much deeper so you have good clean edges (exactly the opposite of what you might be trying to do in noncompositing shooting, where you're trying to get shallow DoFs).

Do that by either stopping the camera down as much as possible (you will probably have to have a much brighter set, crank up the light)... or shoot with a smaller-sensored camera. This is one of the cases that a little 1/3" camera might be very preferable over your big-sensor camera.

Some really kickass keying (such as Ultimatte) might be able to handle the fuzzy edges pretty well, but in those cases especially you'll have to make sure your key lighting is absolutely perfect with no green spill at all.

Film purists looked askance at Lucas for shooting the last Star Wars movies with a 2/3" camera rather than a big-sensor camera (such as the Panavision Genesis) or with real 35mm film... but those movies were so composite heavy that I'm sure betting it made doing all the matte work easier since the depths-of-field were much deeper.


T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com






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Kim Huston
Re: 5DM2 and Green Screen
on Sep 18, 2009 at 5:44:43 pm

Thanks for the info! Sounds like it's best to just not have anything out of focus around the keying edges.

It's unfortunate because that whole commercial (linked) is in front of the green screen and we wanted to use the new 5D camera.

I'll check out those keying programs/plugins though. I definitely could use the help of software specifically designed to do it.



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Todd Terry
Re: 5DM2 and Green Screen
on Sep 18, 2009 at 5:54:09 pm

Yeah, I think that's going to be one of those cases where the 5D proves to be the wrong tool for the job. A "regular" video camera would likely result in a much cleaner key in that instance.

I'm not sure even high-end software such as Ultimatte would be able to nicely handle such extremely soft key edges... but it might. Keep in mind though that it's not cheap, and the plug-in itself might be more costly than even the editing software itself. For example the Ultimatte AdvantEdge software (for FCP, Premiere, After Effects, Avid, etc.) goes for well over a thousand bucks... actually I think it's more in the $1300-$1400 range these days. Pretty hefty change for a plug-in, but well worth it if you do tons of greenscreen.


T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com






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Kim Huston
Re: 5DM2 and Green Screen
on Sep 18, 2009 at 6:06:49 pm

Ah ha.... Well that's not going to happen! I'll probably just try some more masking and feathering in After Effects.



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ulf lindstrom
Re: 5DM2 and Green Screen
on Oct 18, 2009 at 9:15:38 pm

Try to get hold of shake. They have discontinued it at apple but in the end it was by far the best keying program FOR the money. There is a few better programs out there but then you need a big budet. I'm running it every day for all kinds of stuff. there is still some good free macros floating around out there. I would recomend Highend3d.com. There you can find all kinds of macros for green screen issues. One set of macros that maybe could help you is Alpha Edge erode bundle that somebody made and put up there for free(thanks!). Hard keying, dialate erode, alpha edge erode and then spill supressor might do the trick ???

Best U.


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