- Banned
- #1,221
Pawel Achtel
Banned
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- Oct 12, 2007
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- Location
- Tasmania
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Of course, depends on what you want to achieve. From "artistic" point of view, anything goes.
However, from the optimal exposure point of view, I would think that, other than macro, you would struggle to fully expose red wavelengths underwater.
From my article:
"...Water is a very effective colour filter of about 0.12 red. This means that you
lose 1 stop of red for every 2.5 m. ...
...If the lighting is mounted on the camera you lose 1 full stop of red
with only 1.25 m from the subject. This is because light travels from camera to
the subject and back. ..."
Consequently, "daylight" or "tungsten" light balance do not make any sense underwater.
CRI will always be heavily skewed towards blue or green, even if you start with perfect 100% (which, BTW is only produced by halogen tungsten, but not LED, HMI, MH or other common light sources). But, as it travels through the water, even warm colour temperature tungsten light will be depleted of the spectrum around red wavelengths.
By the time it gets to the camera it would be often cooler than a daylight source on the surface. One can roughly estimate that, for a subject more than a meter away from the camera, a 3200k light mounted on the camera would be rendering it as if it was illuminated with 6500k light on land.
And, this is not including the ambient light!
However, from the optimal exposure point of view, I would think that, other than macro, you would struggle to fully expose red wavelengths underwater.
From my article:
"...Water is a very effective colour filter of about 0.12 red. This means that you
lose 1 stop of red for every 2.5 m. ...
...If the lighting is mounted on the camera you lose 1 full stop of red
with only 1.25 m from the subject. This is because light travels from camera to
the subject and back. ..."
Consequently, "daylight" or "tungsten" light balance do not make any sense underwater.
CRI will always be heavily skewed towards blue or green, even if you start with perfect 100% (which, BTW is only produced by halogen tungsten, but not LED, HMI, MH or other common light sources). But, as it travels through the water, even warm colour temperature tungsten light will be depleted of the spectrum around red wavelengths.
By the time it gets to the camera it would be often cooler than a daylight source on the surface. One can roughly estimate that, for a subject more than a meter away from the camera, a 3200k light mounted on the camera would be rendering it as if it was illuminated with 6500k light on land.
And, this is not including the ambient light!


