Thursday 6 February 2014

WINTER EXPOSURE


Have we had enough of cold and snow yet? Unfortunately, it doesn’t look like it’s going away any time soon.

So – if you have the itch to get out and take some photos anyway but are disappointed with the results, the problem may be with exposure. The photographic kind, that is. The camera meters (measures) the light coming through the lens and tries to ‘average’ the exposure to a mid-grey (referred to as 18% grey).

With Evaluative (Canon-speak) or Matrix (Nikon-speak) metering, the camera reads the light over several zones in the viewfinder. If a bright scene covers most of these zones, the computer in the camera will calculate the exposure based mostly on these bright zones. In winter scenes – guess what – snow tends to dominate the scene and the camera tries to expose it to a mid-grey. So, if your winter shots are a little dark, that’s the reason.

There are two fixes for this: spot/partial metering and exposure compensation. I find the latter is the easiest solution so I’ll address it first.

 
Exposure compensation is a means of overriding the camera’s metering, by allowing you to over- or underexpose by an amount chosen by you. It’s normally controlled by pressing the +/- button and turning the command wheel on the camera. As you do, a bar graph (depends on the camera) will indicate by how many stops you are changing the exposure.

Since the snow caused your camera to underexpose, you need to dial in some overexposure or + exposure compensation. I typically use about one and two-thirds stops, but you may need to use something different depending upon how much of the scene is occupied by snow. Just don’t forget to dial it back to zero when finished, because it won’t go away when the camera is turned off.
 
Partial or Spot metering relies on something that has a mid-grey tone (although it can be a colour like facial skin) centred in the viewfinder. It effectively ignores all the white snow around it and exposes based on the face or mid-grey object.

I hope this helps, because there’s nothing I can do about the weather. If you need a little more help,  check out my photography courses at www.filmscapes.ca

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