But I digress...
I want to show you two photos and I want you to think which is the black board and which is the white board.
It is very hard to tell, right? The problem with cameras these days, especially the fully automatic ones, is that it does all of the thinking for us. During the film SLR days, and I am glad I was able to shoot some with film, you have to do the thinking for the camera, not the other way around. You have to know how to expose the film and you have to do a lot of thinking before you take the shot. With digital cameras now, the film is measuring the exposure for you - set to its own devices, the camera will make everything look like middle gray - that is, simply, if you take a photo of a white object, the camera will think that the scene is bright and the camera will underexpose the shot. Conversely, if you take a picture of a black card, the camera will think that the scene is dark and it will overexpose the shot. In both instances, the camera left on its own, will produce a middle gray shot, as I've shown in the two photos above.
So how do you compensate for this? If you have a shot that is dominated by white, like a winter scene, then, to compensate for the underexposure done by the camera, you should overexpose your shot. On the other hand, if you have a scene that is dominated by black, like a sunset scene, then, to compensate for the overexposure done by the camera, you should underexpose the shot. How much you compensate will depend on the shot. So, for the examples above, first I underexposed two stops to bring out the black board.
For the shot on the right, I had to overexpose by two stops to bring out the white board.
(Now you know which is which regarding the first two photos.)
But, you can be deceived by the LCD at the back of your camera. So, if your camera can display the histogram of your shots, then, for a black-dominated shot, the histogram should be leaning towards the left; a white-dominated shot should have a histogram that is leaning to the right.
|Properly underexposed shot.|
|Properly overexposed shot.|
Just be careful that the histogram does not get out-of-bounds towards the left or the right - that simply means that you won't be able to get any details in the picture that is either overexposed or underexposed.
So, when the snow sticks this winter, make sure you adjust the correct bias for the picture that you are making.
And, again, before heading in, make sure you insulate your camera before you bring it out inside the house. My discussion of that can be found here. And as always, keep warm and dry and enjoy this winter season. The cold climate should not be a deterrent in making great pictures.
And lastly, these ideas are not limited to winter scenes. If you have a white dominated scene, overexpose; if you have a black dominated shot, underexpose. And check your histogram.
Shots of the board made with a Canon 5D Mark II with Canon EF 24-105mm f/4L lens. Shot of the wife tubing down the slope made with a Canon 7D with Canon EF-S 17-85mm f/4-5.6. Shot of the sunset taken with the Canon Powershot G12.
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