optical

Etymology

optic + -al

adj

1. Of, or relating to sight; visual.
   Strabismus is an optical defect.
2. Designed to assist or enhance sight
   A microscope is an optical instrument.
3. Of, or relating to optics.
   Refraction is an optical effect.
4. Of, or relating to visible light.
   Optical telescopes don't work when it is cloudy.
5. Incorporating light-sensitive devices.
   An optical switch opens the door automatically.

noun

1. (film">film) Any special effect requiring laboratory work on the film">film.
   If you plan to output back to film, opticals and effects can be shot on film or generated by computer and then transferred to film. 2006, David K. Irving, Peter W. Rea, Producing and Directing the Short Film and Video, page 294