The design of photographic lenses for use in still or cine cameras is intended to produce a lens that yields the most acceptable rendition of the subject being photographed within a range of constraints
For many other optical devices such as telescopes, microscopes and theodolite where the visual image is observed but often not recorded the design can often be significantly simpler than is the case in a camera.

• Photographic lenses also include those used in enlargers and projectors.
• Designing a lens that reproduces colour accurately is also important
• Photography is a highly competitive commercial business and both weight and cost

From the perspective of the photographer, the ability of a lens to capture sufficient light so that the camera can operate over a wide range of lighting conditions is important. Designing a lens that reproduces colour accurately is also important as is the production of an evenly lit and sharp image over the whole of the film or sensor plane.

Later developments adopted designs in which internal elements were moved to achieve focus without affecting the outer barrel of the lens

To be useful in photography any lens must be able to fit the camera for which it is intended and this will physically limit the size where the bayonet mounting or screw mounting is to be located.