View Full Version : Green video in gym


Ethan Cooper
April 20th, 2008, 08:43 PM
Here's my little mystery:

We had a reception in a gym this weekend and no matter what I did to white balance 2 of my 3 cameras, both came out with a green cast or tint to their pictures. One was our trusty old VX2000 and the other was a HV20. Our FX7 was unaffected by the problem.
I started out with all cameras in auto white balance, but when it became apparent there was some sort of problem going on I tried to manually white balance both the VX and the HV20 on a table cloth to no avail. They both seemed to think the room was green no matter what I tried. The FX7 never read the light as green at any point.
I seem to think it has something to do with a particular type of lighting used in gyms, but I can't track it down and have no explanation for why it only affected 2 of 3 cameras. Anyone know what it is exactly and if there's something you can do about it. Better yet, do you have an explanation for why it would affect a VX2000 (3 chip CCD) and HV20 (1 chip CMOS) but not a FX7 (3 chip CMOS)?

Greg Boston
April 20th, 2008, 09:13 PM
Same thing happens with regular old fluorescent lighting. You have to have a minus green filter on the lens (or light source) that counteracts this effect.

The problem is that the light output has a more or less dual spike in the green spectrum. Another way to counteract this is with a custom color matrix in the camera. My F350, along with some other cameras, have this as a preset.

As to why the FX7 handled it better, I am as puzzled as you are.

-gb-

Ethan Cooper
April 20th, 2008, 10:26 PM
I've shot in a lot of lighting situations over the past 6 years and this is the first I've ever seen of the green cast I remember reading about with fluorescence. It's not a problem since I can always correct it in post, but I could see it being a major problem if you were doing a live broadcast or something like that and didn't have the proper on camera filtration or in camera settings.

Any good theory for why the FX7 came through unscathed?

Monday Isa
April 21st, 2008, 09:19 AM
It's a sign to get another one (^_^)

Ethan Cooper
April 21st, 2008, 09:22 AM
Funny. I'll get right on that.

Tim Harjo
April 26th, 2008, 12:33 AM
I'm frequently guilty of not doing a good white balance job before a shoot. I usually try one of the auto settings and go with the one that looks the best. I don't worry about it ever because I just fix it in post. not sure what you are using, but i use final cut Pro. I use the 3 color corrector. The one circe on the right adjusts for "whites". I simply move this until I like it.

On that note, I used to make the whites, well... white. Now I adjust it to give it more of a 'mood'. I love working with colors.