Handling difficult light

Right Image: Canon EOS D30, Tamron 70-210mm f-2.8, 1/750 sec at f-8 on aperture priority, Bogen monopod, multi-pattern metering

The best tool your camera has is its built-in exposure meter. If you've read some of my earlier articles including Exposure, you know how exposure meters work and how accurate they are.
 You also know when you need to ignore your meter and calculate the reading on your own. Under normal conditions when photographing middle tone subjects your meter will give good exposures. Middletone has average tonality. It is not black nor white, it is not dark nor light, but somewhere in between.


This is an 18% gray color or middletone

What if you are photographing a black object in snow? Add a little fog to this scene and even the most sophisticated camera meters will be fooled. Lets remove the fog and add some light to the same scene. What if the black object in a snow scene is backlit or sidelit? If the sun is behind the subject or hitting it from the side, it can confuse a meter. Even frontlighting can throw off a meter by several stops. What is the solution or this type of scene is impossible to photograph? If you understand how meters work, you can solve any difficult lighting situation. Lets solve the above examples which can be done in several ways.

It is difficult if not impossible to record a black object in a snow scene and record everything as you saw them. You have to make a compromise. This is true in many cases including ordinary scenes. The best way is to find something middletone that is in the same light as your subject. The middletone object does not have to be in the scene you are photographing. As long as it is receiving the same light as your subject, you can meter this middletone area and transfer the reading to your camera and use this reading to photograph the main scene. A rock, tree trunk, or your own camera bag can be metered. Meter the middletone object and lock exposure in manual mode or press AE-lock button in aperture or shutter priority mode. Recompose and photograph the original scene. Both the black object and snow will fall into place. If you metered the black object or the snow, severe under or overexposure would result unless you compensate.

Black is two stop darker than middletone and white is two stops lighter. You can meter the snow and open up 1/2 to 2 stops depending on the light. Cloudy days may require only 1/2 stop or 1 full stop while bright sun may require 2 full stops of additional light. Sun reflection on snow can fool meters by several stops resulting in severe under exposure. It is best not to meter black objects directly. Black does not reflect much light which can cause overexposure. Meters may indicate opening up 3 or more stops which can wash out the image. In this case, meter something middletone and use this reading to take the picture.

Image below: Minolta Maxxum 9000, 70-210mm f-4 lens, 1/60 sec at f-11, Kodachrome 25, aperture priority, spot metering the green water lily leaves


If there is no middletone to read, in the example I mentioned above, you can still take good reading by metering the snow and opening up 1/2 to 1 stop if it is overcast or up to two stops under direct sun. Incident light meters come in handy under this type of situations. Since incident light meters measure the light falling on the subject as opposed to camera meters which are reflected type and measure the light reflected from the subject, they cannot be fooled by subjects tonality or reflection. You simply hold the meter pointing toward the camera and under the same light as your subject and take a reading. Transfer the setting to your camera in manual mode and shoot. It is not always possible to use hand meters in the field. What if the black object in the snow is a bison or a wolf and you are standing far away (and you should) under different light? Needless to say you have to find another alternative. If there is no middletone anywhere near, metering the snow is the best alternative as long as you open up 1/2 to 2 stops.

All the techniques I mentioned above can be used in any type of lighting condition or any subject. Frontlit, backlit, or sidelit work the same as long as you meter correctly and add or reduce exposure. Strongly backlit requires two stops of additional exposure. If you meter a middletone area which is backlit, you need to open up two stops. Sidelit requires 1 additional stop of light, and no exposure adjustment is needed for frontlit middletone objects. For white add an additional 1 stop and reduce 1 stop for black objects in frontlit, sidelit, and backlit situation. For example, if your meter indicates 1/250 sec at f-11 for a backlit middletone subject, you would use 1/60 sec at f-11. For white subjects in the same example you would use 1/30 sec at f-11 and 1/500 sec at f-11 for black subjects.

This chart shows middletone at 0 and additional adjustments you need to make for lighter and darker tones.

The truth is that you can use any exposure you like as long as you get your shots back exactly as you wanted them. That is what correct exposure means. One thing is for sure and that is your camera or incident meters are life savers as long as you know how to use them. Regardless of the type of camera you own or its metering modes, learn how each works and know when to ignore them. Sorry to tell you this, but no matter how much you paid for your top of the line camera, it is still not 100 percent accurate regardless of what the owners manual says.
So, where is my black wolf in snow example picture? Unfortunately, I don't have one but if I ever come across the scene, it'll be a dream come true. I just hope I can quickly find something middletone to meter.