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Old Jan 25, 2007, 1:47 PM   #1
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I've been playing around with hotlights and had my niece and her boyfriend come over to experiment. I'm using 200 watt clear bulbs from GE. I was getting good skin tones in some shots and yellow tones in others. I was shooting from the same place and the lights were all in the same place. Why would this happen from one photo to the next? (see photo 1 and 2).



I was pretty happy with photo 3 after some editing. I had to separate them from the background to adjust the brightness/contrast and also had to add more of the background since mine wasn't large enough (photo 4 before editing). I have another piece of material that I'm going to sew to make it large enough. Any other comments or suggestions? Thanks a bunch.


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Old Jan 25, 2007, 2:49 PM   #2
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Just a suggestion, I might be totaly wrong lol

I think that on indoor shots under tungsten, that zooming in

with a lense with the same iso setting, increases the F stop

and makes the shot lean toward the red or yellow part of the

light spectrum. There are photographic software programs that

allow you to adjust the colour temperature, so as to re-adjust

the colour balance back toward the blue end of the spectrum

and thereby fixing the shot colour temperature to your satisfaction.
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Old Jan 25, 2007, 3:21 PM   #3
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Do you have line regulation problems? In other words does the voltage in your studio vary quite a bit, like brown outs? You would have to measure at the plug where your lights connect.

If you shot during a brown out the filament could have cooled enough to change the colour temperature.

You may wish to investigate voltage regulators if this is your problem.
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Old Jan 25, 2007, 5:11 PM   #4
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There is a shareware prog zoner photo studio 8


that lets you adjust colour temperature

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Old Jan 25, 2007, 6:36 PM   #5
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First picture is: f4.5 1/80 sec. Pattern metering exposure compensation -2.3
Second pic is : f5.6 1/60 sec. Pattern metering exposure compensation -2.3
Why the different exposures under constant light? And why so much exp comp? Also, are you using auto white balance or setting a custom one? The exif doesn't say. That alone could cure your problems.

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Old Jan 25, 2007, 8:01 PM   #6
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When shooting under constant lighting (unless it's florescent), you should set your cameras White Balance to incandescent or tungsten. Auto is better suited to outdoors shooting with bright to cloudy conditions.
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Old Jan 25, 2007, 11:00 PM   #7
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Agreed. Do not use AUTO white balance.

You might also want to consider using more wattage. When I shoot under hot lights (usually only for video) I have something in the neighbourhood of 5-6000 watts of light. I also use quartz lamps, not incandescent because of the wattage. And yes, they are called *hot* lights for a reason.

Your AF will work a lot better too.
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Old Mar 7, 2007, 4:05 AM   #8
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I agree it's a white balance problem.

I looked at shot two, it's really not badly exposed, it's just the white balance looks off. I checked the exif, it says auto white balance. It also shows you used multi metering.

Auto white balance is spotty on alot of DSLRs, especially in incandescent/tungsten light. Normally you are best of choosing the incandescent setting there. (Though for best results, you might set it manually.)

Anytime you are in a fixed lighting situation like that, where the light shouldn't change much, you only have to get it right once and you are good for the rest of the shoot. So get it right at the start, with a few test shots, and you can forget about it. Instead of auto having to figure it out again every shot.

The same is true for the metering. If the the lighting won't change much, switch off multi metering and go with average metering--it's more consistent. You might have to then take some test shots and dial in some exposure compensation until you get it right, but once it's right, you can forget it and shoot. (And again here, manual exposure would be even more consistent--but might require more experience).

Autofocus normally works well enough to rely on, and normally your subject is moving some anyway. But there are situations where you might apply this thinking to focus as well. For example, suppose you want to shoot a series of shots with a subject in one place, and the camera on a tripod in a fixed place, but want to experiment with different lighting. Switching to manual focus and getting it precisely right from the start would give one less variable to rely on the camera for on a shot to shot basis.

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Old Mar 7, 2007, 9:04 PM   #9
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I'm incline to agree that the issue is both auto white balance and auto exposure issue. They're changing because of the differing sizes of the faces in the image which of course change the amount of the background included in the calculations. If you encountered this and white balance/exposure were manually set once I'd then suspect voltage variations.
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