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Author Topic: Bushfire light effects on digital camera  (Read 2720 times)

OnyimBob

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Bushfire light effects on digital camera
« on: January 01, 2007, 04:22:14 am »

Can anyone exlain to me how the following shots came about?
Used a Nikon D70, tripod, without flash (red image) then with flash. It was actually 5:40 pm (with daylight saving that makes it mid-afternoon - sun still halfway down), and the smoke from nearby bushfires (americans call them wildfires I think) completely blotted out the sun to the extent that I needed a torch to set up the tripod. That brings me back to my question. What was the camera seeing in the first shot that it shows as broad red-coloured daylight? Imagine the second shot without the flash and you'll have an idea of what it was actually like, the white spots were bits of ash falling.

[attachment=1444:attachment]
[attachment=1445:attachment]

Am I correct in thinking this was perhaps infrared?
Any clues anybody?
Bob
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BernardLanguillier

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Bushfire light effects on digital camera
« Reply #1 on: January 01, 2007, 06:15:21 am »

Quote
Can anyone exlain to me how the following shots came about?
Used a Nikon D70, tripod, without flash (red image) then with flash. It was actually 5:40 pm (with daylight saving that makes it mid-afternoon - sun still halfway down), and the smoke from nearby bushfires (americans call them wildfires I think) completely blotted out the sun to the extent that I needed a torch to set up the tripod. That brings me back to my question. What was the camera seeing in the first shot that it shows as broad red-coloured daylight? Imagine the second shot without the flash and you'll have an idea of what it was actually like, the white spots were bits of ash falling.

Am I correct in thinking this was perhaps infrared?
Any clues anybody?
Bob
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My un-educated guess would be that your camera was set to Auto White Balance, and mistook the red light for some incandescent artificial light that it tried - but failed - to correct for.

The second image was probably automatically set to flash WB (meaning near day light) and this produed colors closer to what you were expecting.

If you shot in raw, you should be able to get more predictable colors by converting the image using day light White Balance (around 5500 K).

Cheers,
Bernard

Jonathan Wienke

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Bushfire light effects on digital camera
« Reply #2 on: January 01, 2007, 11:43:37 am »

Bernard has nailed the cause, and the solution to your problem. When shooting with flash, many cameras will automatically switch to flash WB automatically. On auto WB, it is common fo the camera to guess WB incorrectly in the conditions you were in. If you shoot RAW, you can set WB however you like in post during conversion.
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OnyimBob

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Bushfire light effects on digital camera
« Reply #3 on: January 01, 2007, 06:32:32 pm »

Thanks to both of you Bernard & Jonathon.
I'm sure you're both right, but I'm still a bit puzzled. The shot without the flash was shot with a WB of 4800. Adjusting it right down to 2000 is the only way to get acceptable results colour wise, but where was all the light coming from? It was DARK, night time dark.
Was it just the exposure settings? ie 1/5 sec, f/3.5, ISO 1600.
Sorry if I seem thick.
Bob.
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Jonathan Wienke

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Bushfire light effects on digital camera
« Reply #4 on: January 02, 2007, 02:43:52 am »

Firelight, lights from nearby cities/towns, moonlight, starlight, etc., all filtered through the smoke to lower the color temp. Your exposure settings sound about right for that sort of thing.
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