In photography, wide angle lenses typically have a focal length that is much shorter than the diagonal dimension of the image sensor (or film). For a full frame 35mm digital camera, the diagonal measure of the sensor is about 50mm, and this is considered a “normal” focal length. Wide angle lenses have a focal length shorter than this (typically 12 – 35mm). It’s important to understand the characteristics of shorter focal length lenses so that you know how to use them in your photography.
Of course, wide angle lenses take in a wide field of view. They also have a larger depth of field when compared to normal or telephoto lenses. And they are also very good at helping you vary the perspective of your image. What’s perspective? It’s the relative scale of nearby and distant features. This is what I want to discuss today.
Take a look at the two photos below. Both have the same subject matter. They were both shot with similar focal lengths, but the perspective differs greatly. In the first photo, the nearest tree is only about 1/3 of the length of the fort in the distance. In the second, the same tree is almost as tall as the fort is long. This is a huge change in the relative size of the image elements.
How can you achieve a similar effect? Wide angle lenses exaggerate the size of things that are close, and make things farther away look smaller. The wider the lens, the greater this effect is. When you have a wide angle lens on your camera, you can move closer or farther away from things so that you can control the relative size of close image elements and those that are farther away.
I wasn’t happy with the composition of the first image. I made the second by moving in closer to the trees. Since they were nearby, and the fort was in the distance, the trees were enlarged much more than the fort. Simply adjusting where I placed the camera allowed me to vary the relative size of the trees and fort.
Castillo de San Marco at sunrise, 17mm focal length, f/4.0 @ 1/800 sec, ISO 200
Sunrise at Castillo de San Marcos #4, 16mm focal length, f/11 @ 1/13 sec, ISO 200
Now that you understand this basic principle of photography, you too can use it to control the relative size of the elements in your composition. I will leave a discussion of why wide angle lenses aren’t used for portrait photography very often as an exercise for the reader.
©2010, Ed Rosack. All rights reserved.
