Still another thing to consider is if you want the convenience of a lens featuring auto focus, or if it’s no big thing for you to focus manually. This may also make a difference in the price of your lens. While you can use the same brand of lens as your camera body, there’s also high-quality lenses made by manufacturers like Tamron, Sigma and others that may be less expensive.

(Note: On popular cropped sensors camera such as the Nikon D-3 series or Canon 1D/5D series, keep in mind that the cropped sensor increases the focal length magnification factor 1.6X. For an equivalent to a 50mm lens on a full-frame camera, you’d want a 35mm f1.8 as an equivalent on cameras with 1.6X cropped sensors. It works out to a focal length of 56mm–not quite 50mm, but fairly close.)