Chapter 5. Understanding Lenses
Many digital cameras come with zoom lenses so you can zoom in or out to meet different photographic opportunities. Zoom in on a subject and you can capture a close-up portrait or distant action at sporting events. Zoom out and you can capture a wide-angle view of a large group, a roomy interior, or of an expansive landscape. The ability to change your angle of view as you frame your image is one of your most powerful creative controls. On digital SLR cameras, you can also use a zoom lens, but there are also many fixed focal length lenses available, some of them designed for specific purposes such as close-up photography.
Modern camera lenses are designed on computers, ground to critical tolerances, coated with chemicals to improve light transmission, and then mounted in precision barrels and mounts. The primary function of a lens is to gather light reflecting from a scene and focus that light as sharply as possible onto the image sensor in the camera. A high-quality lens does this very well, but to get the most out of what it has to offer you should know a few of its characteristics and how they affect your images.
In this chapter we look at lenses and their use in digital photography. This will give you the background you need to use lenses more effectively and more creatively.