suitable for green/blue screen shooting?
 

I was wondering if anyone has yet had the chance to shoot and green or blue screen footage. If so I would love to hear thoughts, or better yet get my hands on source clip to run some test key pulls.

I shot some video a couple weeks ago with green paper on computer and phone screens and put in the user interface after the fact. It worked great. I had no codec related problems. The biggest problem was motion tracking as the screens were often obscured and sometimes went off the screen.

The only issues that I had were the typical chroma key issues - splash, uneven lighting, that sort of thing.

I used AE CS3 for keying and motion tracking. For the keys, I just slapped in a number of standard chroma key effect layers to deal with the various color ranges present on our crummy paper job. Growing and softening the edge a bit made it really forgiving.

I wasn't doing anything tough like smoke or hair, though I did have a number of wine glasses in front of one screen. The glasses moved quickly, so I could be a bit sloppy.

Of course, the camera shoots 4:2:0, so it won't be great for fine detail, and it has aliasing, which could be an issue in some cases. If you can soften the key edge a bit, aliasing won't be a problem.

I will be testing this out in the following weeks. Wondering how shallow DOF would affect the keying being able to blur the BG and keep really sharp edges on the subject...we'll see! I'll do a comparo with my 150 which works wonderfully well.

Ah, that's where my main concern is: hair. The bulk of the work I intended for a camera would be talking heads against green screen, where aliasing around the hair would likely be very problematic. I wonder, with the right lighting (backlighting and hair light) would these issues be resolved?

Fortunately (or unfortunately), I haven't had to shoot hair over a greenscreen with the 5D2 yet.

I'll be very interested to hear your thoughts afterwards, Robert. The ability to pull good keys (and by good, I mean as near flawless as practically possible) is a make/break point for me. If it means investing in more lighting, the price of the cam can justify that... but the key has to be good.

let me share one secret that I use with my 150 and will use with the T2i...and this works for most of what I do which is an actor talking at the camera not moving...I turn the camera portrait so the actor fills most of the screen. I always shoot progressive. Bigger I can get them in the 16x9 window, better resolution and keyability once I get to post. Then I can flip them back to normal and scale it to my needs. Had to build a mount for my camera to be able to do this but I rarely have to touch the fine adjust parameters in post. Also I have the actor about 8-10 feet in front of the screen so there's not a chance of bleed.

hate to break it to you Robert, but that technique isn't much of a secret. ;-)

I have seen some instances where talent was a good 10-12 feet from the screen but still managed to have some green reflection on the shoulders. They thought distance made backlighting the subject unnecessary; it didn't.

I knew I wasn't the first. Just wanted to bring it up so more people can produce better quality work!

Don't have time to play too much today but T2i is in my hands and I took this as my 2nd picture...50mm f1.4 on full auto. Can't wait to shoot some vid!

Not much you can do about spill but it's easy to manage in the compositing app. I've been using the 550D the last few days on an all-greenscreen shoot and it appears to be holding up very well. I've attached a photo framegrab from the 550D video and then a picture of the behind-the-scenes setting. As you can see, conditions are far from ideal, but the camera doesn't seem to mind!

Robert, from a compositing perspective, I always try to leave extra room around the actors to allow for a little flexibility in post. You can always zoom in on a shot but it's a little difficult to zoom out.

Would love to see some finals from these greenscreen shoots.

Jan interesting lighting.
I take it that since it's such a small space that you didn't light the green screen.
So was your solution to use china balls to light both talent and green screen evenly?

Will have a pre-trailer in about 6 weeks with most of the cool shots and backplates.

I lit it in such a way to raise the ambient light in the entire room. The greenscreen was at about the same fstop as the subjects, and I added a bunch of kickers as needed to create the environmental highlights for each scene. Above all, the intention was to create even, neutral lighting so that there wouldn't be any changes in exposure when walking around the space. In that regard, the setup did succeed. Low-budget doesn't always mean cheap!

Most of the stuff I do is just talking heads with no real movement. Just have to watch their hands which can easily get lopped off if they go out of frame. I have the actor hold their arms out to set framing (yes with some wiggle room) and never lost a hand doing that! Only done a few shoots where I needed the actor to move around and of course you have to frame it accordingly.

So has anyone shot anything on greenscreen with these cameras yet? I've got a green screen shoot next week and am going to do some tests with the T2i but wanted to see if there's any feedback on the subject yet.

"Ah, that's where my main concern is: hair"

I shot a couple of chroma keys shots with my 550D at NAB that were very well lit.
I used the faithful preset with sharpening set at 2. I think if I had set the sharpness to 0 the key would have been a little better.

I then used Keylight with Fusion 6 to try and pull a key. The stair stepping was unbelievably bad! I got a little better key using Fusion's Ultrakey.
I have been pulling high end keys for years and this is some of the worst footage I ever saw for chroma keying. I can pull a much better key with Beta SP.

After I messed around with the footage for 1/2 hour or so I got a decent key, but nothing I would brag about.
I have pulled chroma keys with Red that were infinitely better. Test before you do a paying job!

Shot this promo with a hand painted green canvas in my garage over a year ago, just a week after I got the Canon 5D. This shot keyed so well, and just in Vegas, done in about 5 minutes. I had tried similar shots with my FX1 and HV20 footage , and it was always a bear. Admittedly some green spill neeeded some cleaning up, but for a quick dirty job, I was amazed how easy this went.

Try something with fine hair detail and report back. :)

This short 30" was all done with the 7D and ex-1. Most green shots with 7D. Not particular problems with it. Also consider that keying was done with Vegas, without any external plug-ins. I did find easier to get "clean" edges with the ex-1, but 7D was workable as well. I am also attaching a photo of the green screen setup (incomplete - we are getting the floor section of it on thurs).

Carlo Zanella
The Santa Fe TV Show

Carlos,

The attached image appears to be a still picture not a frame from the video therefore it tells me nothing about how the video keys.

In the video, the keys of the girl look pretty poor (perhaps it's Vimeo).

And the tennis racket looks poor too....

I believe this article has been discussed somewhere on the forums, but I thought it was relevant to this thread.

Canon T2i/550D HDMI Output Footages Jay Friesen's Blog

summary: It seems that the hdmi output (which cannot be recorded while you are recording on the camera) produces uncompressed video (much better for keying).

caveot: you can't get some of the display stuff off the screen so you have to crop your video down to 720p to make it work.

PS. Chris: nice work on that promo.

So...on a T2i, you can't record externally from the HDMI without getting the heads up display on the clip? Can't you shut it off?

You don't happen to know whether it's possible to shut down any similar status displays on a 5D?

It seems like it's screaming for a Flash Nano...or a KiPro as an external recorder to me.

That's what I'm wondering. How frustrating to have that forced upon us! I suppose we can hope that a Magic Lantern firmware for the T2i (if it ever emerged) would solve that problem. ;-/


The KiPro is precisely what I was thinking too.

This is from a shoot I did to compare between the 5D and the pany hpx2000. (ignore the motion tracked mustache) I had no problems keying it. just convert your footage to prores 422 LT and you should be fine

Our most recent short (below) uses green screen extensively throughout the final scene (shot on a 5DmkII). We didn't have a lot of fine hair or anything to worry about, and we weren't going for realism with the effect, but it worked reasonably well. I did run into some issues though - there were fine lines in the key edges that almost reminded me of interlace artifacts despite the fact that it was progressive footage. I believe they are a result of the 4:2:0 color sampling, and was able to minimize them with a 1 pixel vertical blur in the blue channel. We converted directly to Prores and worked with that footage in AE using keylight - I suspect adding an intermediate noise-reduction pass with neat video or the like during the initial conversion process would improve the results. This was made as part of a timed competition though and we didn't have time to wait for the render.

Hardest part we had was keeping good looking edges between both sharp foreground elements and out of focus background elements. Settings that looked good for the foreground would result in too hard an edge where the soft background edge should blend into the plate, but fixing that would give us a fuzzy edge on the parts that should have been in sharp focus. Not sure if this is due to something specific in the camera footage or just a general problem with shallow DOF and green screen.