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View Full Version : Green Screen - Need help with Lighting & camera mode



Jebs19
04-09-2008, 09:19 PM
I am doing a short film and I have the HVX200 and I am using a green screen. I have 2 work lights lighting the green screen and only 1 softbox for the subject and 1 backlight. The camera is on 1080i/30fps F5 and the iris is as open as it can get.

The 2 main problems I'm having are: The green screen is showing rays of light and the lighting isn't even on the green screen. How can I make it more even or do I need to get better lights than work lights (500 Watts for each side) ?

The lighting for the subject is not that bright and I have to open up the iris all the way and it's not even lighting, even when I use a bounce board.

Can someone please give me some suggestions?

Thanks

wgzn
04-10-2008, 12:48 AM
wow - you are on the track for big failure. 2, 500 "work lights" arent gonna cut it for lighting the screen unless youre just doing a headshot - and probably not even then. you need about 4x that wattage. what you need are a couple of these:

http://www.filmandvideolighting.com/4ft4banksystem.html
rentable from most decent camera/grip shops.

and if youre using worklights for your screen lighting, i have to wonder what your green screen is made of? that matters as well...

not trying to be an ass here - its just that greenscreen shooting aint simply a matter of plopping a subject and lights in front of a green wall...

im not sure what the "rays of light" youre mentioning are. but id guess its because your worklights arent wide enough. and are hot lighting just parts of the screen.

you also need space. 8 to 10 feet minimum between the subject and the green surface and another 8 to 10 from subject to camera. otherwise youre gonna get huge green spill. thats why all the cheapo-local-tv spots you see have people ina sparkly halo. you will often need a 3rd (or should i say possibly a 4th) light, as a secondary backlight (generally purple or orange gelled) to cancel the spill

cheezweezl
04-10-2008, 01:28 AM
dont worry so much about making the background one continuous shade of green. that's old school thinking. modern keying software can handle a wide range of greens. concentrate more on keeping the spill off of your subject and lighting your subject well.

DO SOME TESTS!!!!!

really. this will be what saves your butt. you will learn more in one test than you can pick up here in a week.

worklights are incredibly harsh and may cause more bounce (spill) than a softer light. maybe try diffusing them with something. rent some silks or get some gels. better yet, rent some lights....

as far as your light issues, the hvx is a hog but not that much. if you have 2, 500w work lights plus a softbox and backlight and with iris open you are not exposed, something is wrong. what is your shutter speed? nd filter on? at standard sgutter and nd off, 1.5-2k of light should get you exposed unless you are shooting the side of a ship.

beyond that, more details get you better answers. maybe be more specific with exactly what you are shooting and camera settings.

wgzn
04-10-2008, 01:50 AM
dont worry so much about making the background one continuous shade of green. that's old school thinking. modern keying software can handle a wide range of greens

true - ISH. but the less latitude you give "modern" keyers, the better your key will be. and thats what separates a good key from a good enough key...

craigbowman
04-10-2008, 01:59 AM
Light the screen using soft even light. (Kino flo style)

Keep subject(s) far enough away from screen so you can provide separation with back lighting on them to avoid spill. Then set key and fill to match lighting of your composite plate.

Eljoninjo
04-10-2008, 02:24 PM
First use reel chroma fabric/paint (sorry cant be said to many times).
If you don't want to spend alot of money...
If your story is outside you might use the sun as a light.
You can always buy some cheap floresent light wich gives pretty smooth light, or get some cheap nylon to soften your work light. But then you need some more light.