Sunday, December 20, 2015

Northern Exposure

Properly exposing a snowy scene can be a bit tricky, but once you understand the basics it will become easier. Essentially you want snow to appear white in an image. You do not want it to be too gray or dark, or too light so that there is no detail or texture in the snow.

The trick is to first evaluate the scene you are looking at, and the kind of lighting conditions that exist. Exposing for snow in sunlight will be different from the exposure needed on an overcast day. This image was made on a very overcast day at the Grand Canyon with low, even light. In addition, the scene has a mix of dark and light tones. In this kind of situation, the basic meter reading your camera gives you will most likely be close to accurate.

But on a sunny day, OR when most of the scene is snow-covered with very little if any darker tones, the basic meter reading will result in an underexposure most of the time.  Why? Because all camera meters are designed to provide a reading for middle gray tones. Aim your camera at an all-white scene, OR an all-black scene, and the camera's meter will provide a reading of middle gray in both cases. An all white scene will be underexposed and appear middle gray, and an all black scene will be overexposed and appear middle gray.

So what do you do? When shooting a snowy scene on a sunny day, or a scene that is mostly snow, use your exposure compensation dial and set it for a one-stop overexposure. Take the shot and look at the histogram. If you do not have any blinkies, and / or if the histogram is not too far to the left (the dark side), then your exposure is good. If you have blinkies in large areas, go back to zero on the exposure compensation dial. If the histogram is too far to the left, increase exposure compensation to 2 stops. 

The more you understand your camera and how light meters work, the easier it will be to know how to set your camera in a variety of shooting situations.

Shutter Speed 1/100 sec.  Aperture f/10.  ISO 200.  Camera: Canon 5D Mark III.  Lens: Canon 17-40mm f/4L, set at 25mm.  Handheld.

TODAY'S QUOTE: "Snowflakes are one of nature's most fragile things, but just look what they can do when they stick together."  --Vista M. Kelly

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