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From: limoges@ac.dal.ca
Newsgroups: sci.bio
Subject: Re:Speed of human eye?
Message-ID: <3400@ac.dal.ca>
Date: 11 Feb 91 13:22:01 GMT
Lines: 10
Organisation: Dalhousie University, Halifax, Nova Scotia, Canada

I recall from a physiology course I took a number of years ago that the human
eye can 'see' 20 frames per second. That is to say that the latency of a 
picture on the retina is approximately one twentieth of a second, such that
movies projected at 24 frames per second (used to be standard for 8mm movies,
the film, not the video kind) seem smooth, while at 16 the action seems to be
jumpy. Also this latency is what is exploited by the many magicians that 
specialize in slight of hand tricks; just execute the trick fast enough that
the eye has no time to 'see' the action.

Hope this is to your satisfaction, Bertrand Limoges