 Posted 12/18/2007 10:34:59 AM
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This past weekend we got some snow (& ice) and my dog loves playing in it ... it's always a challenge for me taking good pictures with the snowy background. Does anyone have some helpful tips they'd like to share?  Thanks!
-LindaMy Profile
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Posted 12/18/2007 12:28:32 PM
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| Believe it or not, you want to set your camera to overexpose at around +1 or +2. The reasoning is that your camera will purposely underexpose for the bright white snow and you're left with grayish snow. Just remember to take several shots with different exposure settings and examine the histogram. Good luck.
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Posted 12/18/2007 1:19:20 PM
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If you capture images in RAW format, you can fine tune the white balance after the fact. Cameras set on AWB (automatic white balance) can be fooled by a snowy scene producing either a too blue or too yellow color cast. Using AWB is the right choice, but you may need to correct for a missed natural color cast.
That said, snow in the shade with a blue sky overhead will have a natural blue cast because the snow is reflecting the blue sky. Snow in the sunshine should be mostly white.
In general, snow and white clouds are sun reflectors. Your camera's light meter will try to make snow in the sunlight an 18% grey underexposing the entire scene. I agree with Will's comments on exposure. And, always a good idea to bracket exposures.
In severely cold weather, you can have condensation problems on your lens and (gasp!) your sensor. The key is to avoid taking your equipment abruptly from a warm, humid inside location to a very cold outside location. I usually take my equipment out to my cold vehicle about 45 minutes ahead of leaving for my shooting destination.
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Posted 12/18/2007 2:59:53 PM
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That actually happened to me in reverse. I was in a nice cold air conditioned car and then went out to a very warm humid beach. 
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Posted 12/22/2007 2:56:36 PM
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Thanks, Will & Richard! I appreciate the help and am looking forward to a chance to try this (we're expecting rain & temps in the 50's tomorrow though so the snow may soon be disappearing  ) I confess I'm not as careful as I should be about not 'shocking' the camera with a drastic temperature change  I will have to learn to be more considerate of my equipment  Thanks again for taking the time to reply and I'm sorry I didn't respond sooner ... been busy, busy, busy with holiday baking, shopping, wrapping, etc  Edited for a typo
-LindaMy Profile
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Posted 12/22/2007 3:03:18 PM
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Richard, you got it backwards. The problem comes when you bring things from cold to warm humid environments. The water condenses out of the air on the cold surface. Going the other way around there's no water in the air and the saturation level of the air near the warm surface is higher so actually will evaporate any moisture that might be on your camera. No need to take stuff out early, but definitely be careful bringing it in from the cold (leave in camera bag to act as an insulating barrier).
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Posted 12/22/2007 3:28:26 PM
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Zeke Smith (12/22/2007)
Richard, you got it backwards. The problem comes when you bring things from cold to warm humid environments. The water condenses out of the air on the cold surface. Going the other way around there's no water in the air and the saturation level of the air near the warm surface is higher so actually will evaporate any moisture that might be on your camera. No need to take stuff out early, but definitely be careful bringing it in from the cold (leave in camera bag to act as an insulating barrier).
While I agree the situation is much worse going into a warm humid environment, there is also risk going into a cold environment from a warm house, which is the question posed by the original poster regarding snow/winter weather. Twenty below zero degrees Fahrenheit is a different ballgame than any temperatures above freezing. The evaporation rate in cold weather is extremely low. Condensation of moisture on glass and sensor surfaces is serious business.
I guarantee you, that even in low humidity environments (only zero humidity on the moon and outer space, I think), you can fog a lens or sensor by jumping into the cold. It's all relative (humidity). (LOL!!!!)
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Posted 12/22/2007 3:38:05 PM
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I knew my saying no water in the air would be a problem. Ok, to get more technical:
If you're in a warm environment with 60% relative humidity and you take your camera outside where it's -20F and 100% humidity (unlikely but let's do it for illustration), the air immediately surrounding your camera and sensor heats up decreasing the relative humidity to something like 20% (I don't have my Thermo book handy so I can't look up saturation tables for different temps). Nothing will condense. On the other hand, if you take your camera that's -20F and go into a room that's 70F, 60% humidity, the air immediately around the camera will cool down and the relative humidity will reach 100% and water will begin to condense on the surface.
An analogy is this: take a glass of icewater into a warm humid room and you will have condensation on the glass. Take a glass of hot tea out into the cold outside and you will not have condensation.
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Posted 12/22/2007 3:48:29 PM
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