Archived posting to the Leica Users Group, 1996/04/23

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To: leica-users@mejac.palo-alto.ca.us
Subject: Re: The autofocus Leica M...who cares?
From: Eric Welch <ewelch@gp.magick.net>
Date: Tue, 23 Apr 1996 09:35:33 -0700

At 09:19 AM 4/23/96 -0400, you wrote:

>	The magazine was Popular Photography:  they ran the test some time
>last year and their results were striking, but they used a magnifier on 
>the camera.  Apparently, autofocus sensors can only resolve 40 or 50 lpmm 
>(if my memory serves me correctly - I am going to go to the library and 
>check this out).  I am not sure that an unassisted human eye can do any 
>better than that.

Right, that's the magazine. I don't read it, it was reported on Compuserve.
But resolution isn't the problem, and accuracy varies between systems, and
even in systems. Like the EOS1n is three times more accurate in focusing
than the A2E when using lenses of 2.8 or faster. Contrast also plays a role
in focusing, which may be one reason why we see better than it would seem we
could resolve. 

Another thing is the ability of the camera to stop the lens at the right
spot when it's focusing. I could know exactly where to put the focus, but
being able to execute it quickly might be compromised as opposed to a human
who racks the focus back and fort and observes how focus goes in and out,
which is why AF is best for fast moving subjects.

I guess the point of this thread was, though, what value it has, and in that
context, it's valuable for those who need it. And it's going to have to be a
big decision for Leica to give it a whirl, especially considering the
conservative nature of Leica users. Fortunately, they correctly assume the
most important part of the camera is the glass. <g>
Eric Welch
Grants Pass Daily Courier


Replies: Reply from Gary J Toop <gtoop@uoguelph.ca> (Re: The autofocus Leica M...who cares?)