pentaprism

or pen·ta prism

[ pen-tuh-priz-uhm ]

noun

1. a prism that has five faces, a pair of which are at 90° to each other; a ray entering one of the pair emerges from the other at an angle of 90° to its original direction: used especially in single-lens reflex cameras to reverse images laterally and reflect them to the viewfinder.

pentaprism

/ ˈpɛntəˌprɪzəm /

noun

1. a five-sided prism that deviates light from any direction through an angle of 90°, typically used in single-lens reflex cameras between lens and viewfinder to present the image the right way round

Word History and Origins

Origin of pentaprism¹

First recorded in 1935–40; penta- + prism

Example Sentences

Panasonic still retains a faux pentaprism hump at the top of the Lumix S1R, so it’s not like you’re saving much in the way of bulk or space required when packing your gear for a shoot.

From The Verge

Photo: Fujifilm Photo: Fujifilm Photo: Fujifilm An inch thinner than the GFX 50S By eliminating the faux pentaprism hump that housed the generously sized electronic viewfinder on the 50S, Fujifilm has shrunken its medium format shooter to its most portable form yet.

From The Verge

The hump in the middle — which simulates the pentaprism chamber of single-lens reflex cameras — houses the pop-up flash and sits only slightly higher than the two large control dials at the top.

From The Verge