focal length

a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | z

Click one of the letters above to advance the page to terms beginning with that letter.

focal lengthsearch for term: The distance between a lens or mirror and its focal point. This length is usually stated in terms of the diameter of the lens or mirror; for example, a reflecting telescope of focal length f/4 has a focal length that is four times larger than the diameter of the primary mirror. Generally, longer focal lengths permit higher magnification, but smaller fields of view.