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Color temp question


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#1 underexposed

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Posted 23 March 2002 - 09:45 PM

Can someone explain how the color temp (4800 degrees Kelvin) affects the pics and what is best and why. Thanks for any help.
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#2 MikeO

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Posted 24 March 2002 - 08:25 AM

Color temperature is basically the temperature a "black body" in physics would have to be heated to to give you the color of light you're talking about. It is measured in ēK (0ēK is absolute zero). For example 5500ēK approximates sunlight at noon. Color temperature affects you two ways. One is that your strobe emits light of a certain color temperature to approximate sunlight. The other is that you can set white balance to accept what "white" would look like under a certain temperature of light. For a much more thorough explanation, see:

http://cybaea.com/ph...correction.html

Mike

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#3 underexposed

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Posted 24 March 2002 - 10:50 AM

Thanks
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#4 davephdv

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Posted 24 March 2002 - 01:16 PM

In UW photography the color of your subject will be determined by your strobe's color temp. The lower the color temp. the warmer the image will be. I find the color temp of the Ikelite strobes (200 and 125) to be perfect (4800). I got a Sea and Sea 90 for macro and found its color temp. (5400) to be too cold. I had to use the diffuser to reduce the color temp. to 5100 to get what I condsidered acceptable images. I have known other sea and sea strobe users to complain about the color of their exposures. In several cases upon suggesting that they use the diffuser they noted considerable improvement. But this is all subjective and you will have to expirement to determine what exposure you like. As in the above post remember you can work with your white balance as well.
Dave Burroughs, Nikon D300, D2X, Subal housing, DS160 strobes

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#5 Arnon_Ayal

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Posted 30 April 2002 - 04:29 AM

I have 2 questions:
1. what is the normal flashes (on ground) temperature?
2. How can I change the colero temperature?

Tn'x, alto
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#6 james

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Posted 30 April 2002 - 04:50 AM

Not sure about the normal "land" flashes, but sunlight is around 5,000K - 5,500K

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#7 MikeO

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Posted 30 April 2002 - 06:22 AM

Most "normal" flashes are set up to give you something like 5000-5500K. I only know of one underwater strobe, the Subtronic Mega-Color (and it is very expensive -- on the order of $2000US) that allows you to select from two color temperature settings (4300K, 5300K). With a digital camera, you can approach the problem from the other side of the equation and set the white balance to compensate . . .

Mike Oelrich
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#8 davephdv

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Posted 01 May 2002 - 07:06 PM

As I mentioned above you can change the color temperature of with a diffuser. Remember you can make your own with any translucent material. Also note as mentioned above you are shooting digital and can change your white balance. Finally their is Photoshop. With a film camera you can alter the film you are using to achieve a different warmtn to your shot. Some UW digital cameras come with UW filters. They are designed to be used without strobes but the film cost nothing so you can experiment to your heart's content.
Dave Burroughs, Nikon D300, D2X, Subal housing, DS160 strobes

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