Archived posting to the Leica Users Group, 2001/01/05

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Subject: Re: [Leica] Anybody use the 75 summilux on a .72x M6?
From: Al Edwards <>
Date: Fri, 5 Jan 2001 12:36:32 -0800 (PST)

> It is a great lens, but beware
> of focussing wide-open.
> Occasionally you have to have
> the camera/lens combo 
> optimised for close range focus
> (usually in the 6-10 feet range). 
> It can throw the focus 
> and be 2-3" off - and at 1,4
> you will see it. 

> Tom A

Yep. Mine focuses too far, but not by much. Tom A
says it more concisely than I can, but I struggled
with and solved this issue, so I'll elaborate.

At 1 meter, mine focuses long by 7mm, which doesn't
mean much in terms of missed shots at f/1.4.

Between 6 and 10 feet is the critical area, since
life at f/1.4 can be nasty there. Here, it's
long by 2-2.5 inches, but CONSISTENTLY so: if I focus
on your eyes, your multiple ear piercings will
be crisper than your eyes. Again, this is consistent
behaviour, so I treat the split image as a marker
of where the beginning of the zone of focus is, and
assume I'll get the 4-6cm behind that point in focus.
So if I want your eyes in focus, I nail the stud that
pierces the tip of your outstretched tongue. If
in the foreground is convenient, just roll back
a mite from what you want.

Some notes:

- -This technique is not as distracting in practice
as it sounds, and only required that I shoot
one test roll of a high-contrast subject at 1m, 2m,
and 3m and note the error. After 2-3 rolls of
practice, it becomes automatic. You're sweating
so much over focus at f/1.4 that the security
of knowing the error more than compensates for
the additional hassle of adjusting. It is
now subconscious for me.

- -I don't feel it's necessary to buy a .85 m6 for this
lens. It might help, but is it worth another $1500+?
If you would otherwise spend that $1500 toward a
second Ferrari, then yes. Short of that, I don't know.
I used to sweat bullets trying to focus an
85/1.2 on an SLR -- fast lenses
of this length are always tough. The limiting factor
seems to be subject movement and operator error, and
not the precision of the rangefinder.

- -This could be due to rangefinder misalignment in
my .72 m6 -- both of my 75 Summiluxes exhibit
identical behaviour, so it's not likely due to
lens threading or cam issues -- but, as my m6 works
perfectly with my other lenses, I'm not
going to fix what ain't broke. After the next
CLA, I'll have to shoot another test roll and
adjust my technique.

- -Know your equipment (DUH). Taking the time to
shoot test rolls, note the results and make
adjustments pays handsomely
with the 75 Summilux. Practice improves your
images because it improves you, not your

- -Axioms of the 75 at 1.4: Beyond 15 feet, there is no
law; Beyond 20 feet, there is no God; "...long
distance focusing is a game of chance" (Erwin Puts).

- -As noted elswewhere in these posts, at f/2 these
6-10 foot problems diminish considerably.



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