Re: Making pictures with the M Leica

["Charles E. Love, Jr." <cel14@cornell.edu>]

At 01:51 PM 2/25/97 +0100, you wrote:
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>>   Date: 	Tue, 25 Feb 1997 04:33:52 -0500
>>   From: Dan Cardish <dcardish@microtec.net>
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>
Just to get the attributions right:

Charles Love wrote:
>   >>When focusing a rangefinder camera, you
>>   >>should start either at infinity or the closest setting, and move the
ring in
>>   >>one motion until the two images coincide--do not rack it back and
forth, as
>>   >>you might with an SLR, to improve the focus.  The reason this works, I
>>   >>understand, is due to the nature of the mechanical linkage between
lens and
>>   >>rangefinder--racking it back and fortyh produces inaccuracies.
>>   >
Then Ben wrote:
>>   >This is an old machinists trick. As the bed screw of a mill or lathe wears
>>   >it develops slop. When moving the bed to make a cut you back up so
that the
>>   >screw is engaged fully when your tool touches the work. Same with the
>>   >rangefinder.

Then Dan wrote:
>
>>   Let me see if I understand this.  Start at one end of the focusing scale.
>>   Focus by turning the focus ring in one direction until images coincide.  Do
>>   not rack it back and forth.  If I overshoot and am not satisfied with the
>>   state of focus, what do I do?  Go back to infinity and start over?
>
Then Christof wrote:
>Dan,
>
>if you are not satisfied, you have to adjust (of course).
>The way I understand it is, that you have the possibility to see immediately,
>when it is in focus. So more precisely it might say: start focusing quick and
>slow down the focusing speed until you made it. 
>
>With an SLR you might not be able to determine the first time that you are in
>focus.
>
Now, my turn again!  As Ben suggests, my original point doesn't have
anything to do with whether a RF or SLR is easier to focus.  It's rather
that if you focus a RF by racking it back and forth to get the focus right,
you introduce errors due to the nature of the mecanical connections
necessary for a rangefinder to work.  So: your habit should be to start from
one end of the lens's travel, go toward correct focus (slowing down if you
need to), and stop when you get there.  If you mess it up, I'd say start
over--that's what I do.  It really is a matter of habit, and starting over
doesn't take that long!--Charlie
Charles E. Love, Jr.
CEL14@CORNELL.EDU