Thursday, January 17, 2008


There's no snow where I live. Summer is hot and humid. For two or three months, it's unbearably humid, with temperatures to about 40 degrees Celcius. Winter temperatures might get down to about 5 degrees. As far as seasons go, that's pretty much it. No spring - not really. No autumn - no colour changes, no leaves falling.

So to travel to a different climate brings new photographic challenges. Snow, for example. Snow can be difficult to photograph, particularly when it is in large quantities in the scene that you are capturing. In the picture above, of a fire hydrant in Chicago, there is a relatively small amount of snow. Where it is a larger portion of the scene, you need to be careful that your camera's meter isn't fooled into thinking that the scene is too bright and that it should reduce the exposure.

The problem is that light meters are programmed to average a scene's exposure at middle grey. When the scene is predominately white, as in this snow scene below, the camera thinks that it should be grey. The photo on the left was taken at the meter's reading of the scene, and you can see that it is clearly underexposed, with the white snow rendered grey as a result.

To produce white snow, the exposure must be increased. Most cameras have an adjustment called exposure compensation that lets you increase or decrease the

exposure from the one that the meter suggests. For scenes like this, there are a couple of things to remember. Firstly, use your camera's play-back function to check how the image looks on the LCD. If it looks underexposed, dial in some positive exposure compensation. In a situation where it appears to be overexposed, then a negative adjustment is called for.

Secondly, bracket your exposures. Take a few exposures with different levels of positive and negative compensation. This allows you the option of choosing the best one later.

EXIF (main image):
Nikon D70; Nikkor 17-55mm DX; ISO 200; 1/400 sec; f2.8


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