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How to get white snow – Winter shooting tips

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Why are my snow pictures dull grey?

Here’s the first in some winter picture taking tips that we are putting together. A common complaint we hear when people bring their winter pictures in is – “my pictures look dull,” “the snow looks grey, not white.”   Read on for the short and the long answer.

White snow with camera at plus 1 
The picture you see is the one above with white snow . . .
 
The picture your camera captures has grey snow as shown below.
Why is my snow grey   
 
So the question is – How do I get white snow?
 
The short answer is you need to overexpose by using the Exposure Compensation +/- feature on your camera. Using the exposure compensation automatically makes this adjustment so your camera still can remain fully automatic. In the case of a Nikon you would press the +/- button while rotating the control wheel until +1.0 shows in the display. Your owners manual will explain this in detail or feel free to stop by the store to learn how to make the settings on your camera. Be sure to take some test shots so you get the hang of how this works. If less of your image is taken up with the snow you can try the + 0.7 or + 0.3 setting to reduce the brightening effect.
 
After taking your snow photos just remember to turn the exposure compensation +/- back to zero.

The more technical answer

This is all caused by a camera’s meter system which is designed to see “18% grey” ( the solid gray image to the left ). Essentially anytime you take a picture that is predominantly white or black the camera will make the wrong exposure. Since the cameras meter can only see grey, an “average scene”, we only need to make adjustments when our scene is predominantly white or black. Luckily 98% of what most of us shoot are scenes with average lighting values and need no adjustment.
 
Predominantly white scenes ( think Snow, white sand beaches, clouds )will be moved toward grey so we must over expose from .5 – 1.5 stops to get true white by using the +/-.
 
Predominantly black scenes ( think black cars, black buildings, black sand beaches )will be moved toward grey so we must under expose .5 – 1.5 stops to get true black by using the +/-.
 
 A future tutorial will explain how to get perfect exposures using a grey card.
 
 
 

Using histograms to further understand

For those familiar with histograms we can further look into diagnosing our exposure. The histograms are shown below with both our camera exposure and with exposure compensation set on + 1.0. Histograms are available in almost any digital camera including point and shoots and most imaging programs like Photoshop Elements.

A histogram is just a map of the tonal values in our image from black (left most point) to white (right most point) with the height representing how much of the image is at a particular level of brightness. Your histogram will look the same in camera and when you open that image up in your imaging program.


^Black                   Middle^Grey                        White^

Grey snow historgram - normal exposure 

In the grey snow example above our histogram has a good deal of room before the white point on the right so the image represented by this histogram is a shade of grey not white. By overexposing one stop ( +/- +1.0) the camera automatically adjusts and allows 1 extra stop or twice the amount of light. As you can see from the histogram below we still have a small amount of room before the white point (this room indicates we have not blown out our highlights. If this histogram started all the way to the right and did not build to a peak, this would indicate over exposure and blown out highlights. The fix would be to reduce the exposure compensation from +1.0 to +0.7 and check again. The peak will move to the left each time you reduce your exposure. More on histograms in an upcoming tutorial.

White snow when overexposed histogram  

Please let us know what you think of this tutorial and let us know what else is causing a challenge in your photography.

   

Written by John Tworsky

March 1st, 2010 at 5:46 pm

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