White Balance or Exposure...Which First? at DVinfo.net

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Old July 6th, 2010, 09:06 AM   #1
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White Balance or Exposure...Which First?

Hi everyone:

Please set a novice straight -- should I set camera exposure first and then white balance or the other way around?

Thanks!
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Old July 6th, 2010, 10:31 AM   #2
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I would say get a rough exposure, set white balance then fine tune your exposure.
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Old July 6th, 2010, 10:40 AM   #3
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Set the white balance first, because that will usually stay the same for most locations. Usually the first question ypu ask yourself if you're lighting a scene is about the colour temperature, then the lighting levels required.

The exposure can then be set as required as you're filming at a location and this can change or need adjustment.
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Old July 6th, 2010, 10:42 AM   #4
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Just remember to take your white balance cards with you wherever you go!
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Old July 6th, 2010, 11:05 AM   #5
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As Tim suggested get a close exposure setting first then set the WB and then bring in your subjects, set up the scene and adjust exposure for final settings and make adjustments as necessary.

I have noticed that Color Temp does change slightly if you drastically under or overexpose.

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Old July 6th, 2010, 11:38 AM   #6
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When I say take the white balance first, that just involves pointing the camera at a card which is roughly exposed in a ball park (not over exposed), it's a mechanical process, you can just let the auto exposure do it or use the zebras. It's nothing to do with the scene exposure.
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Old July 6th, 2010, 05:33 PM   #7
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Excellent. Thanks, everyone!
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Old July 6th, 2010, 10:25 PM   #8
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I agree with Garrett, Tim and Brian's REVISED statement - it's important to not have the whites "blown out" or drastically underexposed but if you're in the ballpark, go for it. And yes, I do touch up exposure AFTER white balance - not often but SOMETIMES white balancing will make enough of an exposure difference to require an iris BUMP one way or the other.
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Old July 8th, 2010, 08:21 AM   #9
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Some Cameras give strange Auto White Balance results if you are in manual exposure so it is good to know how your camera reacts when White Balancing. I usually use Auto Iris when White Balancing if I am not using a Preset White Balance.
This doesn't mean I haven't already set up my shot or started to see what exposures might work.
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Old July 29th, 2010, 12:09 PM   #10
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Auto exposure for white balancing is good, but you can also expose to roughly 70% on the white card. I never had a camera that reacted strangely to a manual exposure of ~70% (not saying there aren't any)

The exposure will be different, because a white object will usually not be 70% in the final shot (more like 90-99%).

In my experience color saturation can change a bit when over- or underexposing (try a HPX500 and overexpose skin-tones: welcome to pop-art!) but the white balance stays the same. It is important however that the whitecard is not overexposed during white balance, because that can lead to a wrong white balance.
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Old September 5th, 2010, 05:56 PM   #11
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In the old days of online edit suites each suite or shop would have a broadcast grade monitor which was (in theory anyway) calibrated and on which the colours could be relied. Now that most non-broadcast editing is done on uncalibrated monitors - or am I the only one with bog-standard 24inch monitors - isn't the whole question of white balance fairly academic?

In those day we used BVW507 cameras and the white/black/white balance sequence was always done with the iris on auto. The camera itself closed the iris for the black sequence. The notion that any white balancing can be done with any accuracy if the camera is over- or under-exposed is surely a non-sequitur?

Finally, most of our work is multicam and the impracticality of white balancing three cameras for different illumination of a subject from three angles means we rely on the presets and tweak any glaringly wrong colour at the colour grading stage - though obviously I use that term quite loosely.
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Old September 6th, 2010, 02:16 AM   #12
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I commonly use the preset unless the lighting source is unusual or I want to do a quick fool the white balance. I often gel the lights anyway, so a "correct" white balance is just a jumping off point.

One drama cameraman I know put it that the preset version can be more interesting than the white balanced version.
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Old September 6th, 2010, 02:44 AM   #13
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Brian makes a point that event people as I am mainly now have to resolve and that is whether we try to "correct" genuine and real changes in the colour of the light during an event.

The specific instance I have in mind is a wedding reception in a marquee during a typical UK summer with strong daylight falling on one side of the marquee. Being a wedding there's usually plenty of white around, but the light is anything but.

Firstly there's the colour of the tent and any interior decoration - often they have a chiffon-type drape making a more pleasing appearance.

Then as the sun sets the colour temperature of the light falling on the marquee drops, and the light illuminating my subjects changes accordingly.

What do you do?

The options seem to be to

a) explain to the clients, one of whom is convinced her dress is brilliant white and hasn't changed all day, that the unadjusted pictures are what the scene really looked like or

b) "chase the white", adjust each sequence, even shot, in post to maintain a balance between the white of the bride's dress and some semblance of the other colours, especially skin tones which will, of course, also change (sometimes unacceptably) as you chase the white.

c) try, as I'm trying to do right now, to apply a little correction to the first shot ie do an "in post" white balance and then let any changes happen to the ensuing shots. I guess this sounds like a simple combination of a and b but in reality it seems to me to be the most difficult to achieve.

Even after 30 years experience I don't think I've found a satisfactory answer to the problem and I'd be interested in what others do. I should perhaps also add that camera 3, positioned to record the guests' reactions, had a clear plastic curtain facing away from the sunlight ie east as a background - but I think that might be asking too much for a written, remote solution!
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Old September 6th, 2010, 04:01 AM   #14
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Often those mixed lighting situations it's a matter of finding the best balance for an image that looks good, is appropriate for the subject matter and keeping this consistent during a sequence supposedly taking place at the same time of day .
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Old September 6th, 2010, 03:18 PM   #15
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For neutral colours white balance should be set with correct exposure. However, manipulating white balance and mixing colour temperature is all part of the art and you should learn everything you can about how to do it.
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