Newsgroups: comp.robotics
Path: brunix!uunet!decwrl!sdd.hp.com!caen!uvaarpa!murdoch!uvacs.cs.Virginia.EDU!smc8p
From: smc8p@uvacs.cs.Virginia.EDU (Shawn M. E. Carnell)
Subject: Re: camera autofocus mechanisms
Message-ID: <1992Nov3.130415.6850@murdoch.acc.Virginia.EDU>
Followup-To: Dan Liddell 
Keywords: autofocus
Sender: usenet@murdoch.acc.Virginia.EDU
Organization: University of Virginia Computer Science Department
References: <1992Oct27.182416.3970@murdoch.acc.Virginia.EDU> <1992Oct28.145740.8052@phx.mcd.mot.com> <1992Nov2.170102.4653@netcom.com>
Distribution: na
Date: Tue, 3 Nov 1992 13:04:15 GMT
Lines: 29

In a recent article, Dan Liddell writes:

> Another class of autofocus camera, the SLR with interchangeable
> lenses, seems to have very good performance, according to an informal
> survey of a large group of users over in rec.photo. The autofocus
> mechanisms seem to focus as sharply, and more rapidly, than a human
> hand and eye can.


As far as i know, NO camera lens can focus as fast as the human eye.

Also, Mr. Liddell mentions how autofocus mechanisms have troble with low
contrast sences.  He mentions that in low light situations his friend
Mirai would shine a red cross on a target to help the system find
contrast.  This is typically the way any infrared autofocus system works
on a good 35mm camera today.

If you see a camera with a deep red patch of shiny, clear plastic on it
somewhere, its probably shining a patern of infrared lines on everything
immediately in front of the camera to give the autofocus something to
latch on to.

As far as finding information about such devices, i might try a camera
store.  They may have the numbers for repair shops or manufactures who,
while they themselves might not have the info you need, could give you
another pointer in the right direction.

Shawn
shawn@virginia.edu
