Canon® EOS Digital Photography Photo Workshop

6.1. ZOOM VERSUS PRIME LENSES

Overall, lenses are divided into two main groups: prime and zoom (see figure 6-2). A prime lens (also called a fixed lens) is one that has a fixed focal length, meaning the specification is a single length, such as 15mm or 200mm. A zoom lens has an adjustable focal length, meaning its focal length is a span, such as 24-70mm or 120-300mm. Both zoom and prime lenses can be in virtually any focal length — wide, normal, or telephoto. The following sections look at each type in more detail.

Figure 6-2. Zoom versus prime: Note the difference in how these two lenses are classified. The 50mm prime only has one focal length while the 70-200mm zoom lens has a range. ©Serge Timacheff

6.1.1. PRIME LENSES

Many discerning photographers believe that prime lenses have better quality and produce sharper, crisper images than zoom lenses. This is because there are fewer moving parts and optical elements involved in the lens mechanics. Fewer glass elements means less light and detail are filtered by any optics, and a less complex mechanical infrastructure means more precision.

Prime lenses are generally preferable if you can deal with the inconvenience of not being able to change focal lengths. For example, Canon's 50mm lenses, which provide a very real-world, 1:1 magnification, are workhorses in portrait studios, and many professional photographers choose to move ...