Why does it look like my color temperature is changing?

There is only one scenario where I've seen this before. It was a case of a Conflict-Diamond DVX, where the crystalline structure in the diamond, oscillated at precisely the same frequency as the flourescent bulbs, and the oscillating diamond was able to intermittently turn on/off, the auto white balance! :grin:
 
It's your shutter speed, I'd bet. Put it back on "off" or 1/60th and the problem will go away.

You're most likely using cheap fluorescent ballasts with a low refresh rate and the high shutter speed is interacting with 'em. I would normally expect to see a pulsing in brightness, but I guess in your case it's affecting color. You have to be careful with shutter speed and fluorescents.
 
Andre, I could understand your explanation if the white balance was set to automatic, where the camera would be "sampling" light and the white balance would track in response. But in this case, the white balance is not automatically tracking (or adjusting). It is set to manual. How would this still be the mechanism of color temp drift?
 
The camera white balance remained constant. The lights are the problem. It might have worked better if the camera WB was set to "auto" then mybe it would cycle with the lights.
 
KHendrix2 said:
The camera white balance remained constant. The lights are the problem.
Click to expand...
Oh, I see. The white balance stays constant, but the lights are the ones that are periodically cycling their color temp. Interesting. So, I guess even the "pure" lights still have impurities in their powder/gas (?) which cause them to not radiate (ionize?) with a constant color.

Well, I guess the moral of the story is to either, not shoot with flourescents, or slow down the shutter.
 
Stupid questions... Are the work lights that you can buy for cheap at Home Depot considered flourescents? What are they considered?
 
Barry mentioned it earlier.

I'll bet all the money in the world you were shooting with the shutter function on under fluorescent lights.

Do not do that!

Turn the shutter off if you are shooting under fluorescent!

It involves the cycle of fluorescent lights which has a constantly changing color temp. Whether you use auto white or try and set a white balance manually, you will always have the constant shift in color temp.

We have the same problem with larger cameras like Betacam.

The simple solution is to either turn off the fluorescents and light the scene yourself with other types of light or turn off the shutter. There is no middle ground solution that I know of.

Best of luck.
 
I built DIY Kino's like the type Zoomforce (Jarred Land) showed in DIY and I have no problems with color cycling. I am using Phillips T8 4100k, T8 3000k and their T8 5000k tubes. I shoot 24pn at 1/48 for most shots. Here is my post

http://www.dvxuser.com/V6/showpost.php?p=455611&postcount=69

I will post some client video I am editing shortly. These work well and I manually white balance for each set-up. My DIY Kino's use electronic ballasts not magnetic and they are advertised to be more energy efficient and stable.

Most lower end household fixtures use cheaper magnetic ballasts which are ok for normal lighting but can be problematic for video and film.

S Cannon
 
Last edited:
"I would normally expect to see a pulsing in brightness, but I guess in your case it's affecting color. You have to be careful with shutter speed and fluorescents."

Barry is absolutely right, at work we have the Panasonic AJ-spx800, and it also does the same thing, more so under cheap flouresent lighting. From what I have heard this can be true on a lot of professional cameras when you have the shutter on. I have witness this under settings like an old office, small town gym, and blood bank with flos runing constantly. I just keep the shutter off under flos, all the time.
 
Yeah, don't even use 1/60; just keep the shutter function off. I almost ruined some interview footage using 1/60 under flos because the damn producer thought having the computer monitor in the background made a good composition.
 
You must log in or register to reply here.
Back
Top