View Full Version : XL2 and Blue Screen Video


Don Sommer
January 10th, 2005, 11:50 AM
Hi all...

Just got the XL2 on recommendation of a friend that's "in the movie business". I do a lot of corporate video and have worked with blue screens in the past.

I did my first chromakey with the XL2 a couple of days ago. I was not overly impressed with the results. Now .... I am just a couple of days into using the camera ...so it could be "problem user" and not "user problem" in my case.

I am using Keylight and After Effects for the video. I am getting pixelation in the actual image (apart from the normal "square edges" that DV tape incurs).

I am currently capturing at 30fps using a combination of Lowell floods to light the blue screen, and Chimera to light the talent.

What I am wondering is this:
1. Does anyone else use this camera for blue screen work regularly.
2. What settings are you using on the camera.
3. Do you recommend green screen instead of blue.
4. And any other points of wisdom ....

One main gripe that I do have about the XL2 is the LCD viewer. I was hoping for performance like a TTL based viewer (so to speak) and I find the viewer to "lag" and also be a bit inaccurate in focus. My old Sony DCR-TRV20 has a huge viewplate and tracks far better.

Thanks to everyone in advance for any help with the settings on the camera for blue screen work.

Don

Travis Maynard
January 10th, 2005, 12:16 PM
I have shot one compositing test scince I have had the XL2. I haven't been able to use it much lately cause I have been rather busy, but with the test I shot I came out with some pretty good results. I did notice some little artifacts but it had nothing to do with the camera. It was more of my screen doing the problem and plus Im new to After Effects keying. I used other software to key previously.

Now, about your screen. I have always been told that blue isn't always the best color choice when dealing with video. Blue screen is used with film because film absorbs blue much better. Greenscreen is used in video because video absorbs greens better. I myself have never used a bluescreen, but I use greenscreen regularly, with natural lighting. My greenscreen is 2 4'x8' sheets of plywood painted a fluorescent green. I just lean them up against my house and the sunlight does the rest. This greenscreen setup will not work in all occasions and will not get the best results especially if you need to aim the lighting in certain places for the key.

Anyway, I'm going off topic. I suggest that you try out some greenscreen if you can. See what your results are then. I tested several green shades and it seems an almost "yellowy" green does the best. The brighter the better, I suppose. If you would like, I could post some before and after screen caps of my keying with greenscreen and if you could try to post some screen caps of your problems aswell.

Steev Dinkins
January 10th, 2005, 04:44 PM
Don, I just finished shooting/editing a music video and I employed a green screen for a bunch of shots using the XL2. I too used Keylight in After Effects. I was getting the blocky pixelation as well. Screen Pre-blur was an important setting, but I believe I also ended up using Tinderbox's MatteTool's Spot Cleanup to get rid of the blockiness.

Here are 2 examples of the composites:

http://www.holyzoo.com/111/xl2/video/ScrawlerGreenScreen1.mov

http://www.holyzoo.com/111/xl2/video/ScrawlerGreenScreen2.mov

A test I spent less time on is here:

http://www.holyzoo.com/111/xl2/video/XL2_Green_Screen_Comp005.mov

Another key thing I did was apply 4:1:1 color smoothing in Final Cut Pro, and export either DV50 or Uncompressed before importing into After Effects.

Don Sommer
January 10th, 2005, 08:13 PM
Hi Steev ...

That looks a lot better than what I ended up with. I was able to correct most of the edge spill and avoid most of the edge blockiness ... however ... I was extremely disappointed with the noticable pixelation in the facial regions of the individuals.

Yours seems (facially) a whole lot better.

I am wondering is some of the problem is directly due to the capture.

I am using Premiere Pro to capture on a PC. I used to use Macs (actually for years even before OSX) but got tired of the whole "proprietary" thing and switched to building my own PC's (always been dual Xeons) .... but I basically hate all computers equally now ;-) ... they are ALL to slow as far as I'm concerned and all a money grab .... sorry ... I'm rambling.

My friend, who has worked on TV sitcoms, movies, etc. in the industry for years says that the only really only good way to chromakey is with non-MiniDV cameras and that you will always get some amount of pixelation. I just assumed that the XL2 would perform far better than what I was used to.

What camera setting, lighting system, type of chromakey material did you use .. if I may ask? As I mentioned , I shot at 30FPS in Manual mode. I must admit however, that I was guilty of "overlighting" the actor though. I still find it hard not to add just an extra bit of light .... but each camcorder model is different as well ... and I am still trying to learn the XL2.

Thank you for your reply and suggestions. It is much appreciated :-)

Don Sommer
January 10th, 2005, 09:03 PM
I did find this article on Video Finesse and am going to try it ... since Premiere doesn't have the colour smoothing that Final Cut Pro has.

http://www.neopics.com/bluescreen/

We'll see if I get any better results ;-)

In the meantime, any settings, materials, and lighting info from anyone who is interested in sharing would be GREAT for comparison.

Thanks again ...

Steev Dinkins
January 10th, 2005, 09:33 PM
Don, I believe the color smoothing in Final Cut is essentially blurring channels, so yeah, it could definitely be done from scratch with channel blurring manually. It's interesting to see someone illustrate what's going on behind the scenes of the plugin filter. I'm assuming the filmstrip file is a lossless format, yes?

Regarding the other elements involved, I used a Savage green screen and stands:

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=45497&is=REG

I used 2 Photoflex 500 watt Starlites to light the green screen, and used an Arri Fresnel 650 light as a key with no specific fill light other than what was coming incidentally from the Starlight. I was in a pretty large space finally so I could actualy try all of this out - a large factory. It's hard to find the space to work in. :(

Regarding the XL2, I've been using the Cine Gamma, Cine Color, 24p (2:3:3:2) with a 16x Manual Lens.

I'm still surprised I could pull a decent key from Mini-DV footage. My attitude was that I'm going to key this stuff no matter what and tweak it until it looks interesting enough even if it looks bizarre. Of course on more conventional shots (documentary, news, corporate video, magazine-style) this approach wouldn't fly. I think I could do key work on comedy or reality TV style though. I'd just be afraid to rely on it for serious content work. I love the XL2, but I'm wondering what the HDV format allows in terms of key work. Hmm, is that sacrilege on this board? :)

Maybe Someday Andromeda? http://reel-stream.com/

Don Sommer
January 10th, 2005, 11:02 PM
Thanks taking the time to list your equipment :-)

Since I do a fair bit of keying work ... I'll be picking up some Kinoflow lighting in the very near future. They are EXCELLENT uniform lighting for both actors and screen lighting. My "industry" buddy says that almost everyone is now using them exclusively for shots where before they used pot light spots or floods.

For this corporate shoot ... I'll have to make due with the Lowell kit which are either to hot as a spot ... or have hot edges and dark middle as a flood >:-( ... and the Chimera 500W hooded soft lights.

Thanks also for the camera settings. Since I am new to the XL2 .... I'm still "fishing" for my comfort level ... and every bit of advice REALLY HELPS.

Again.... much appreciated.