Readers will be more or less aware of the standard technique for dealing with your camera light meter’s tendency to underexpose snow. Just dial in between one and two stops of positive exposure compensation to avoid rendering the snow as drab grey/gray, right?
But why not seize the opportunity presented by the snow to convince yourself (or your students/friends/fellow camera club members/your not-listening-anyway spouse/your cat …) that, if you aren’t in a terrible hurry (and, soon enough, even if you are in a terrible hurry), that shooting in manual mode is easier and less complicated than using aperture priority with exposure compensation. Here’s the deal:
Snow is, er, white. You’d like it to be white in your images. But not so white that doesn’t appear to have snowy texture. Actually, what we are looking for, in terms of luminosity, is for nearly white—also known as very light grey—so that it can contain snow-like texture that’ll look like real snow on screen and will print more convincingly than a block of featureless white. You may know that, in any of your camera’s auto or semi-auto modes, if you fill your viewfinder with snow (metaphor!) and press the shutter you’ll get not-so-light, drab grey. Near enough 12-18 percent or “middle” grey. If you are an exposure compensation exponent you may also know that, by dialling in between one-and-two stops of positive compensation, you are overriding your camera meter’s need to achieve an average luminosity of this of middle grey across the image . You may even express this in Zone System terms of your “placing” the snow somewhere between zone seven and eight.
Now, assuming that the snow that you point your camera at dominates your composition, you should be good to go. You can very simply achieve the same thing in manual mode. Better still, you’ll get more consistent results when you move around photographing your subject(s) from different points of view. The consistency advantage is achieved because, unlike shooting in aperture priority with exposure compensation, your camera’s on-board computer won’t be constantly adjusting the exposure as it encounters different levels of reflected light. You don’t want it to do that if the light falling on your subject (the incident light) is consistent. This is particularly useful if your subject matter isn’t, or isn’t only, the landscape. Perhaps your family having fun in the snow? As long as the light is fairly even, this manual method will give you perfectly exposed faces lit by some of the most flattering light available on the planet. Give it a try or, if you are already convinced, do a fellow photographer a favour and convince her/him.