WE have been working on a project called CXL for a few weeks now. In those few weeks we have shot some greenscreen footage for the film on the Panasonic hpx500. The director Sean Gillane explains to me that this is more of a broadcast camera and not the best for Greenscreen extractions. We decided to give it a try since our other option was a Canon 5D Mark ll. The issue that this camera has when trying to pull a good key are the Red and Blue channels. These channels have a tendency to be noisier than the Green channel. Also you end with with this nice white line around the image that makes it really hard to key. Check out my examples of these channels bellow.
Red Channel
Blue Channel
The Canon 5D Mark Two is a great camera and I love shooting with it. To steal a phrase from Stu Maschwitz (his prolost blog is a must read) the 5D is an amazing Rebel camera, and it has done a lot for the VERY independent and not so independent film making community. That being said it still has a lot of issue when shooting on Greenscreen. the main issue is that its output is H264. You end up with compressed footage that you have to try and get a key from. Check out this alpha channel with a lose key pulled, you can see the compression ‘s square artifacts. This will make pulling a key tougher, especially around the fine hair area.
Nice chunk of compression
Compression causing the hair to crunch
In this photo you can see on the back of her hair that its starting to crunch. This is due to the compression. There are tricks around this of course but I would obviously prefer to use a better camera.
Quick comp with crunched hair
One way around the compression issue would be to use a Aja Ki Pro mini. We thought this was going to be our savior for our compression issue. It bypasses the camera’s compression and you get a nice ProRes 422(HQ) file. The only problem was that it didn’t seem to work with the 5D. We could only get a 29.97 FPS and no 1080p. Major let down when we found out that we could not use the Aja Ki Pro Mini.
We have one greenscreen shoot left and I still need to figure out if we should use the Panasonic hpx500 or the Canon 5D Mark ll. I keep going back and forth with this one.
Ill see some keying results with the hpx500 and say “Lets use this one on the next shoot” then I see some keying results with the %D and say the same thing.
We are shooting in a few weeks and I am now leaning towards the 5D. One major reason is because the plate for the GS shoot was shot on the 5D and thats really the only reason.
If anyone has any suggestions feel free to post some comments!
