Archived posting to the Leica Users Group, 1996/12/10

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Subject: Re: 35mm Eyes
From: JayPax@aol.com
Date: Tue, 10 Dec 1996 21:52:34 -0500

In a message dated 96-12-07 23:58:25 EST, you write:

<< I can't fault Leica for being conservative in the matter of putting out AF
 reflex lenses. If precision is the name of the game we play, then manual
 lenses can't be equalled in that class.
 
 Bob Rosen  >>


Bob:

I agree with your conclusions.

I was intrigued by an article by Herbert Keppler in Pop Photo about six
months ago where he reported on a study comparing manual focusing and AF.  In
all cases, manual focusing won out.  He explained that even the most advanced
AF system is digital and the system measures contrast and resolves at some
pre-determined detent (albiet an electronic one) in the system.  Therefore,
the most precise system will always be manual, since you can (all other
things being equal, such as good eyesight, etc) always hit focus right on the
correct spot.  The Af system, on the other hand, will drive focus to the
nearest focus point which it determines, and which may or may not be the
EXACT point of correct focus.

It was very interesting.  It causes me to come to several conclusions:  (1)
Manual focus is going to be the best system in all cases except (a) if you
have poor eyesight, (b) you are doing fast action [though this is not always
going to be the case], (c) you like to have the latest gadgets, (d) you are
lazy or (e) some combination of all of the above.

I believe that Leitz invented an AF system years ago and still holds the
patents on it, but never brought it to market for a number of reasons, chief
of which is that it was not precise enough.  I do not know the details of
this.  Some of you Leica-pundits enlighten me, please.

Jay Paxton