As opposed to a zoom lens, which can move to different focal lengths by rotating a ring on the lens body, a fixed focal length lens is fixed at a single focal length. The most common fixed focal lengths available are 20mm, 28mm, 50mm, 105mm, 185mm, and 300mm, although others are available.

- Traditionally, fixed focal length lenses have been known for creating sharper images than a zoom lens set to that focal length, because the glass quality is better. This has been changing in recent years, with improvements to zoom lens design.

- Each focal length can be specialized to a specific purpose. If you do portraits more than 50% of the time you shoot, invest in a 105mm or 185mm lens. These are actualy called “portrait lenses” because they let you stay a comfortable distance from a subject while taking their portrait.

- Remember the multiplication factor on your digital sensor!!! In order to have a 50mm fixed focal length on a camera ith a 1.5 multiplication factor, you need to get a fixed focal length lens of around 33mm.

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