Lens cover

Although a screw-in cap takes more time to remove in order to take a photograph than a standard lens cap, it is stronger than plastic and therefore more protective.

Friction fit lens caps exist but are quite rare.

Lens caps or covers are often lost, they are not a high value item among photographers, especially professionals, photographers at large events or in large crowds may drop their lens caps and fail to retrieve them, leading to a litter of lens caps.

[citation needed] A lens cap may be tethered to the camera via a string to avoid losing it.

Lens caps are also used in mechanical and/or environmental protection for objective and ocular (outer) lens surfaces in other optical instruments like binoculars or microscopes.