Color temperature and exposure

[Nick Palmieri]

Someone in my camera club asked me this question and I really do not have an answer for him, other than to guess. The question is "Is color temperature affected by exposure time, ISO, f/stop?" I would guess that unless its a very long exposure the answer is no, but I was hoping you guys could help shed some light. Thanks!

[Roger Clark]

Someone in my camera club asked me this question and I really do not have an answer for him, other than to guess. The question is "Is color temperature affected by exposure time, ISO, f/stop?" I would guess that unless its a very long exposure the answer is no, but I was hoping you guys could help shed some light. Thanks!

The simple answer is no, But a different question: is exposure affected by color temperature? The answer is yes. Changing color temperature/color balance changes the histogram in all 3 channels, thus affecting exposure. For example, the light from the setting sun can be quite red and and unless one pays attention to the red channel histogram (and, for example, one only looks at the luminance channel histogram), the camera will overexpose the red channel. Then after sunset, with a deep blue sky, the light is predominantly blue and the camera meter will overexpose the blue channel.

Roger

[Nick Palmieri]

Thanks Roger. Makes sense, I will pass that along to him.