A pentaprism is a five-sided glass block with four active surfaces, two of which are mirror coated. These prisms operate as reflectors and they deflect light through an angle of 90 degrees. Compared to the right-angle prism the image of the subject is neither reverted nor inverted. For this reason,
pentaprisms are also used for shortening of the optical path length. Additionally, the deflected beam is independent of the incidence angle in small confines. Pentaprisms are commonly found in traditional DSLR cameras to deflect the image from the mirror to eyepiece.