noun[usually as modifier]
An area of the focusing screen of some reflex cameras which is covered with a grid of tiny prisms and splits up the image when the subject is not in focus.
More example sentences
- An array of lenticular microlenses may be positioned to accept the output of the microprisms so that the light exiting from the microlenses is a substantially collimated light source.
- Plain screens are available without the central split-image and microprisms, and these are suitable for × 1 to about × 4.
- Be careful to position your eye in the center of the finder to be able to see all the microprisms; some will black out if your eye is uncentered.