White Balance/Zebra Questions:

CClub wrote on 5/24/2007, 2:12 PM
I'll be taping two concerts at the same location this weekend. If I set the white balance based on the lighting, is it set properly even though I'll be moving the camera around a lot with a Glidecam and catching various lighting situations? Does the white balance catch the overall balance of the room rather than a specific direction of the camera?

2nd question: During a concert taping, if I set the exposure manually to ensure that the zebras are showing 70 IRE (Sony 2100's can be set to either show subject AT 70 or subject ABOVE 100), but if I'm moving the cameras around a lot, don't people have difficulty concentrating on continually adjusting the exposure settings? I know it's a mortal sin, but I've typically kept the exposure on automatic, as we do a lot of pans/movement of the cameras during concerts, and I have trouble doing anything but concentrating on getting a good scene captured. My only fear is that if the lighting is set too high, the automatic settings may not adjust correctly and I'll have a lot of blownout images. Any input/experience on this?

Comments

GlennChan wrote on 5/24/2007, 2:50 PM
It is probably best to set both cameras on manual white balance, and balance them before the show starts. Their lights should have a single color of white, so WB to that. AWB will make color matching the cameras painful because it will have to be a shot-by-shot basis.

2- Knee settings on your cameras: The knee applies signal processing / color alteration to your image. Sometimes with extremely saturated colors, the knee processing can do really bad things (seen this happen on f900s). If possible, bring a monitor and get the lighting guys to give you the most saturated lighting possible. Bring a manual for your cameras and see if the settings on your camera can be tweaked to avoid this (i.e. a low knee setting??). Or try this at home. I haven't figured out the solution to this on consumer cameras (some of em don't let you disable the knee), but it's a potential problem that sucks if the lighting guys decide to use really saturated colors.

3- In typical stage lighting, it's really high contrast and you are prone to overexposure. You should probably ride exposure manually, or set AE shift down. Learn your camera well and learn how its zebras look. 100 zebra (instead of 70) may be more useful... it indicates where blowouts happen. A few hits of zebras are good (otherwise you're underexposed), but you don't want big areas of blowouts on the subjects.

4- Sometimes you can co-ordinate with the lighting guys so the overall light level stays the same (so you don't have to ride exposure) and that they won't go super high contrast and use extremely saturated colors. HOWEVER, in my experience most stage lighting guys HATE this. They absolutely hate it because it won't look good to their eyes (though it will look good on video). It goes against their artistic sensibility. They'll sit there and get really antsy. They may agree on particular lighting and then change their mind ( @#$@$#%@#$@! comes to mind). So... YMMV.
johnmeyer wrote on 5/24/2007, 4:58 PM
You can try to do manual white balance before the show starts, but stage lighting has so many colors that it's tough to get a white reference. The alternative is to use a preset. Definitely do NOT use AWB.

If your camera has a "spotlight" feature (Sony cameras have this), it helps some. It basically "dials down" the exposure when it senses a small area of the scene is overexposed. However, it seldom is strong enough and you still will get horrendous blow outs of highlights. While manually riding the exposure is the ultimate way to go, that can be tough when the lighting changes quickly especially if you don't have a way to rehearse and if you have no control over the lighting. What I do in my FX1 is to set about six presets and use the AE compensation. This may be unique to that camera but what it does is add or subtract a given amount from the auto exposure. You still have to manually adjust this depending on the contrast of the scene, but it has the tremendous advantage that when you are zooming and focusing, and suddenly the exposure changes, the automatic feature will still get you close. Then, when you have a moment, you can adjust the up/down as needed.
CClub wrote on 5/24/2007, 5:42 PM
Glenn,
Once again, you are the man. I have a couple very informative posts on the subject of white balance you've done before, but you just hit the two issues specifically how I needed to hear them.

I wasn't thinking about AE shifting down before; that's just what I was looking for. Thanks much.

Edit: John, Just saw your posting. I do have the "Spot light" feature; I'll try that a few times when I get there tomorrow. It doesn't seem to affect it too much as you stated, but it might be helpful. Regarding the white balance issue, the Sony 2100 gives me the choice between Manual balance, Outdoor, and Indoor. If I can get a white reference, it sounds like that would be best to do so manually, otherwise I'll set it to Indoor. Thanks.
GlennChan wrote on 5/24/2007, 5:48 PM
Or go for the classic black and white look. ;)
CClub wrote on 5/24/2007, 5:51 PM
Only if Roy Orbison shows up.
DavidMcKnight wrote on 5/24/2007, 5:57 PM
4- Sometimes you can co-ordinate with the lighting guys so the overall light level stays the same (so you don't have to ride exposure) and that they won't go super high contrast and use extremely saturated colors.

I recently heard a tip that might be useful here, and is similar to what Glenn is suggesting re: exposure. If you can, get the lighting guy to dial up the brightest program in the show and adjust your max exposure off of that so that nothing is blown out.

<edit> My opinion, but use this technique to expose for faces or for whatever is important in the shot. If your camera moves and gets a hit of stage light in it that is over-zebra'd (at the 100 setting), so what. It might make for a cool effect.

craftech wrote on 5/24/2007, 6:49 PM
I pretty much shoot only stage productions.

Don't use anything other than the tungsten preset for white balance.

Don't manually white balance and don't auto white balance. Only the tungsten setting is reliable. If you have a white balance shift setting and are using a Sony camera shift it slightly towards red from the center setting to compensate for for the tendency of Sony cameras to lean toward the blue. Canon cameras can be left alone usually.

DO NOT USE ZEBRAS under stage lighting. The video will invariably come out too dark. Whites are usually over illuminated under stage lights and fool the zebras every time.

Calibrate your LCD or small monitor or whatever you are using against a television or studio monitor and make sure it is accurate. Then use manual exposure and go by the calibrated screen you are watching and trust it. Unfortunately with most Sony cameras you cannot use the "spotlight" setting with manual exposure. Not sure about the others. If you are shooting a concert you probably don't need the spotlight setting anyway and my methods described above should work very well.

John
rs170a wrote on 5/24/2007, 7:18 PM
I've shot 3 plays in the past month and my method was the same for each one.
As mentioned previously, I always go with the 3200 (tungsten) preset.
For exposure, I get the lighting board operator to bring up the brightest scene, set my exposure and, with minor exceptions, leave it there for the duration of the play.
My rationale for doing it this way is that certain scenes are dark to the theatre audience so they should be dark to the TV audience. The only time I'll increase the exposure (by no more than one stop) is if the scene is very dark but my experience has been that that's generally not the case.
Having a good 3 chip camera helps tremendously as does attending at least one full rehearsal if possible.
BTW, I didn't get any complaints about some scenes being too dark.

Mike