Canon Xl-2 And Green Screen Issues
 

I got this note from my FX team chief after his Final Cut Pro books came in.

"One of the issues that he notes is the use of the MiniDV format as being a poor choice for greenscreen use due to aliasing"

Has anyone had any Green Screen issues with the Canon XL-2?

DV in general has low color resolution -- 4:1:1 for NTSC; 4:2:0 for PAL, which is the same amount of info, just arranged differently.

As such, borders between colors are blocky, especially contrasting colors.

Add to it the low spatial resolution of DV.

That said, Serious Magic Ultra II gives some very clean keys.

I work primarily in Vegas, and I've managed some excellent keys as well -- not with the XL2, but with the DVX, but all the same characteristics apply.

Light well. Shoot well. You'll get the best results that way.

Here is a clip from a quick test I did a little while ago with my XL2. 24p

Keyed in FCP. I don't think it's horrible. Pardon the focus check.

http://www.arbourmedia.com/media/ross_in_space_ns.mov

I've done a fair amount of green screen work with the XL2 and as long as the subject is properly lit, the background is properly lit and the camera isn't too far from the subject, it can be quite good. I use Key Light to key the footage (it is part of After Effects). It took me a long time to sort of self teach keying and now I can pull, a really good key.

There are two green screen shots on my webpage. See link below on my sig. The one with me talking about Lyon Films was a touch out of focus, soft, at times, but that was the camera operators fault.

This was kinda rushed in a small apartment but some of it is pretty clean

http://youtube.com/watch?v=qBpQlmS_7Tk

I'll give you this that was some pretty funny [expletive]. Fun idea and some great Walken.

Also thanks folks for chiming in on the subject.

John,

I've done a little green screen work with the Xl2 as well. Like has been said, light and shoot well. I actually used a light meter to check the lighting in a 9 point grid over the face of the green screen.

The other thing you mentioned was FCP. Bring the footage in and apply the 4:1:1 color smoother filter which will help smooth those color transitions. Then apply the spill suppressor filter which has adjustments for tweaking in any spill of the subject, such as around the hairline.

We got good results doing it this way.

-gb-

Here's some more G screen stuff done with dvmatte pro. There might be a law
suit involved as well.

Cheers,
-Dave

http://youtube.com/watch?v=CdSUrtFdXUQ

capture uncompressed if you can via s-video
it looks completely different, and keys are a
snap. Just make sure you light your subject
to the capture window of your NLE (yes, sounds
weird) for some reason it is about 1 stop darker
through s-video than DV.

Will,

That's interesting because this isn't the first time I've heard that using the S-Video out from the XL-2 yields a higher quality colorspace than going DV out. It's sort of like the Sony Z1 which has component outputs that are pre-compression. I've seen this information on another reliable site regarding the XL-2.

-gb-

what's funny is that we've had two of them since they came out
and just tested this 2 months ago. We then used the technique
immediately on two studio commercials with great results.

we recorded to tape while recording uncompressed and just
synced with the DV files for audio. On one shot we failed to record
in uncompressed and had to rely on the DV file. Talk about
nasty colors. You never really notice it until you put the two
side by side.

shoot me an email and I'll show you what I mean.

griffithwb@msha.com

You've got mail...

Will,

What do you use to capture the analog video? How do you control the XL2? Is it just a matter of good old fashioned press play and then hit record at the right time to capture?

Colin

We record DV or use tascam to record audio then just
sync in post from the snap of the slate. S-video is
captured via AJA IO (www.aja.com) with Final Cut Pro 5
on a Quad Mac to the internal hard drive at 8bit
uncompressed (didn't see a lot of quality gain with 10 bit).

We just did the same kind of thing capturing from a FX1
using component HD into a AJA Kona LH. All I can say
is WOW. We conformed to 23.98 and removed interlacing
in After Effects and it looks as good as some SR3 s16 stuff
that was just shot for us...only there is less grain!