View Full Version : Any suggestions for shooting chromakey?


Christopher Glaeser
February 11th, 2006, 11:42 AM
I shot a chromakey test clip last night using full auto, SD, and 60i and everything seems to be working fine. I used an 8x16 greenscreen and five Lowel lights. The Sennheiser wireless with XLR sounds great. In the future I plan to get an SDI card, but for now I'm using DV Rack. I'm guessing I can get better keys by switching from full auto to manual settings and using one of the supplied curves. Any suggestions on camera settings to get great keys using firewire would be greatly appreciated.

Best,
Christopher

Christopher Glaeser
February 12th, 2006, 11:43 AM
Set a custom whilte balance and use manual exposure for best results. Turn the zebra pattern on to avoid overexposure. If the talent does not move, use manual focus.

Best,
Christopher

Kevin Wild
February 12th, 2006, 01:13 PM
The best rule of thumb for any greenscreen shooting is to get a nice even light on the background. To check this, the tried-and-true method is to turn on zebras and adjust iris to see what spots are hot and show zebras. Then add or flag the light until it's even. Once it's even, you should be able to open the iris and see the whole background pop on zebras at the same time. Does this make sense?

The other normal advice: keep the subject far from the background to avoid bleed. Definitely put a backlight on your subject's head & shoulders...this provides separation from the green, too.

Good luck.

KW

Christopher Glaeser
February 12th, 2006, 02:16 PM
... open the iris and see the whole background pop on zebras at the same time. Does this make sense?

Thanks, makes sense.

The other normal advice: keep the subject far from the background to avoid bleed. Definitely put a backlight on your subject's head & shoulders...this provides separation from the green, too.

This is easy to accomplish on the talking head shots, but more challenging on the full body shots where the talent is standing on the key. I currently have four Lowel lights, including two Totas, a DP, and a large Rifa. I've tried a number of configurations, and I can get more lights if needed. The best configuration thus far is the DP and Rifa on either side in front, and the two totas to light the green screen with just a bit of the tota spilling onto the back/side of the talent. I'm thinking one more tota for back lighting may be helpful.

Also, I need to test a couple of the H1 curves. As has been reported in various threads, the H1 is rather flat out of the box, and I need to add some punch. Once I determine all the needed settings, I know the H1 can do this easily, but there are many parameters, so I started with full auto and am working my way through the list.

I should also test something other than 60i. If the talent moves the hands quickly, I can see the interlace artifacts in the SM Ultra frames. I'm guessing Ultra will do better with 30f, but I have not tried this yet to see if DV Rack and Ultra can handle 30f.

Best,
Christopher

Kevin Wild
February 12th, 2006, 02:23 PM
Yes, the back light will make a big difference. Also, think about what you are going to key your subject over. If it's a picture of a place, make sure the light source in the photo matches where you're putting your back and key light.

Let us know how the 30F test goes. I agree that Canon is a bit flat out of the box, but it has a ton of setting controls. I definitely crank up the chroma saturation level. This will help your separation, too.

KW