It was the curved shape of the lens that led to its name being borrowed, in the late 17th century, from the Latin name of the lentil plant, lens culinaris. In French, another word for lens is objectif ...

SEATTLE—Primes are single focal length lenses, which can be designed with a relatively few optical elements and thus are capable of transmitting a lot of light to the film or digital camera sensor.

Lenses are used to bend and focus light. Normal lenses rely on their curved shape to achieve this effect, but physicists have made a flat lens of only three atoms thick which relies on quantum effects ...