As most beginners and amateurs will discover, there are some curious frustrations that come along. Of these, the most common are taking a photo on a bright day of something such as snow only to have it turn out too dark or taking a picture at night and having it turn out to bright. So, why does this occur?

Well, first of all it is important to note that because a lot of the time cameras reproduce more or less what we see with our eyes, it is easy to fall into the trap of thinking that we can just put the camera in fully automatic mode, point, shoot, and get a photo that looks just like what we saw. But this is not always possible, and it is because of the way your camera makes decisions when you press the button.

Unless you are using a fully manual camera, your camera must make the decision as to how much light to allow the sensor to be exposed to. If there is too little light, the subjects of the photograph may appear almost invisible, also known as ‘underexposed.” In reverse, if there is too much light allowed, areas of the photo may be completely white, also known as “overexposed.”

A camera will make these decisions based on the fact that most scenes, most of the time, are comprised of both light and dark tones that average out about the same. This average is commonly referred to as “18% grey.” This premise is what allows the camera to determine how much aperture and shutter speed should be utilized. However, in certain situations, this rule of thumb can break down.

A prime example to better explain this phenomenon is the classic photo of a polar bear in the snow on a bright sunny day. You will use your camera to reproduce this beautiful scene you viewed with your own eyes in a bright, perfect photo. However, because your camera is using its rule of thumb to determine the shutter speed and aperture, it is more likely your photo will depict the snow and polar bear as dirty grey.

The other situation is when you take a photo in dark conditions, perhaps a street at night lit by some streetlamps. Here you want most of the photo to be dark, with perhaps some lighter areas that were illuminated by the streetlights. Instead what you may get is dark areas that are dull brown rather than black, and lighter areas that are overexposed. Again, your camera has assumed this scene, like others, is 18% grey, and has exposed it accordingly.

To manage these situations, you will need to take over control of your camera. This means the camera will no longer be able to make its own decisions. One way to achieve this is to dial the ‘exposure compensation’ setting on your camera. A good rule of thumb to go by would be one stop forward for bright scenes and one dial back for darker scenes. An additional option is to turn your camera into manual mode. This will allow you room to play and experiment with settings as you view them in your LCD screen until you determine the exposure you are looking for.

Tobias Sterling is a keen photography enthusiast who loves to write and share his photography knowledge online. He does so by contributing his articles including Motor Sports Photography Blur and Understanding Photogrpahy Aperture to Clivir.com.