Abstract: Apparatus for selecting the focal length of a camera lens which focal length will provide a desired field size, image size and angle of view. The apparatus has a housing and three lens axially aligned therein: A first lens of the converging meniscus type, a second lens of the plano-convex type, and a third lens system of the biconcave type mounted for axial movement between the first and second lenses. The biconcave lens element is formed of plastic and has a handle means preferably integral therewith which extends through a longitudinal slot in the housing to facilitate such movement. Indicia means adjacent the slot on the housing indicates focal lengths. The third lens system is configured to move within opposed, parallel inside walls of the housing smoothly.