View Full Version : Setting White Balance vs. Low Light


Patrick Smith
October 2nd, 2005, 08:47 PM
Hi.

I have been using my GL-2 for maybe almost a year now. To the point where I'm constantly trying to enhance my shoot to its full potenital.

But the last couple times I've done some night or low light shots I've noticed something when setting the white balance.

When i manually go to set it, i cannot get a good reading. The icon will blink fast and adjust a little bit, but instead of stopping when it has a good white balance, it will continue to blink slowly, and my shots will be better the the normal white balance settings given, but will have a blue tint or not fully look good.

I was wondering how you all get a good balance @ night. Since i use a custom preset on low light shots, does that effect my whote balance setting?

any info is helpful! thanks in advance

Collin Waldroff
October 3rd, 2005, 04:40 PM
I get the same problem with my GL2. Recently I shot two weddings and just used the auto white balance because I couldn't get the white balance, but skintones ended up being really orange/red, so in post-production I had to reduce the chroma in Premiere. Thankfully I have a Canopus edit card and it comes with a plugin where you can reduce chroma without having to render the entire thing.

I think next time I might try getting somewhere in the same kind of lighting where the light is strong (like in a hallway or bathroom), doing the white balance there, and just leaving it. Other than that I think we're stuck with using auto or the presets.

Don Palomaki
October 3rd, 2005, 07:42 PM
Just an observation. White balance relies in part on using gain in the red, blue and green channels to compensate for off-white lighting conditions. If you are at max gain already, there is no gain headroom left to get proper white balance.

And because auto white balance is based on the average image color the CCD seess, it can be fooled by having a strong, dominant color in the image, or by using light sources that do not have a reasonably smooth color spectrum.

Evening and candle lit weddings can be especially difficult because candle light and dimmed incandescent bulbs are very warm (red/orange with a lack of blue).

Patrick Smith
October 3rd, 2005, 08:15 PM
Ya. I def was @ max gain. Maybe i'll try reducing that when setting it up.

Adam Christopher
October 7th, 2005, 12:20 AM
If I'm not mistaken, the best solution is to fill the screen with white (a card) when white balancing.

Graham Bernard
October 7th, 2005, 01:43 AM
I do it this way:

1/- Place the card at/on the object that is going to be captured. No point in sticking it directly in front of the camera, if the area to be videoed is 20 feet away.

2/- Zoom in on the card.

3/- Manually focus the edge of the card - mine has a cross hair to get sharp focus, so this is simple for me.

4/- Zoom out slightly to ensure I have the field "full of card", well at least the central portion.

5/- Do the Man WB. You could be lucky and get a constant "lock". If I don't it is telling me that there really isn't enough light for the camera at that distance and with the light levels to get a WB set. So, I either "live" with it or use a preset that "lifts" the look. In any event leaving it with Auto WB will give you a moving feast of WB when you come to post. Again, the viewer may not be aware of the issues you've had. I'm not suggesting for one mmoment you shouldn't be as professional as you can - this I applaud - but, you/me/we have with this XM2 a 1/4 chip. It aint big.

So, what do I do? I decide whether WB-ing will be of any value and then decide to take at least one of the WB presets available. Auto WB? Well, maybe, if I can live with it in post within the WHOLE look 'n feel of the project.

Bottom line here is gonna GOTTA be light - more of it in the place you need it, OR less in the areas you DON'T need it. What this will do is "pop" the subject from the background. THEN in post you can get funky - if you wish.

My understanding of WB is that it balances the "colour" of the video with respect to the light falling on and being reflected by an object being captured. It balances to that which it believes is "white". Selecting a WB preset is an override that says to the camera, "Ah, so this is what Grazie is telling me IS white, by using the .. . artificial light preset" and goes away and "sets" everything to that. Using manual WB I am overriding the WB presets and "forcing" my own version of that which the camera HAS to accept as being WHITE - and it goes away and balances to that. All this is fine IF there is enough light available, and I get a lock. Now, here's the thing, because I may select, say the artificial WB preset, it still doesn't indicate to me that it has enough light. It is only adjusting everything to a preset template. I wouldn't know! However, using the Man WB I can be informed that the camera is struggling, given the light levels available. Basically, I understand the camera NOT being able to get enough information to "set" WB.

So, and this for our 1/4 camera, what is better? GRAIN from GAIN from the camera OR GRAIN from GAIN in POST? Here I have 2 thoughts:

1/- Done in CAMERA is less time rendering in post.

2/- Done in POST gives me more control but tales more time

. .and the other thing .. too many "changes" in WB-ing within the camera will give me/you a headache in post. It can be done. It is often done with ENG work.

The more I do, the more I have a quick 'n dirty "view" to each and every occasion. I am STILL learning. Oh yes!

Any of this been helpful? - I hope so. If I have missed anything out OR got it wrong please give me feedback . . . . .

Best regards,

Grazie