(physics) a magnetic field with axial symmetry capable of converging a beam of charged particles of uniform velocity and of forming images of objects placed in the path of such beam

A stray patch of brightness in a photographic image resulting from aberrant refractions or reflections within the lens due to an exceptionally bright light source, sometimes one just outside the image proper.

(photography) A lens that allows a camera to focus at very close range to photograph small objects.

(optics) A lens having at least one convex surface, such that light passing through it may be brought to a focus.

A rough, opaque piece of glass of suitable size, design and composition for use, when ground and polished, as a multifocal lens for use in a pair of eyeglasses.

plural of lens blank

A spectacle lens whose magnifying power varies from top to bottom, allowing them to be used for both distance use and for reading

plural of lens board

(photography) A part used for securing a lens to the front standard of a large-format view camera.

(photography, informal) A telephoto lens.