Unencumbered by r/f & cam facts, was RE: [Leica] New User Questio n

["Stewart, Alistair" <AStewart@gigaweb.com>]

Michael,

I'm not sure that this is fully correct, but I don't have all the facts.

I have a 21/2.8, converted to goggles by Reinhold to Tom A's design. The R/F
now is now grossly inaccurate, which I knew going in to the conversion. I'm
happy to trade R/F on a 21 for full frame viewing w/o goofy V/F - most of
the time.

I scale focus the 21, and for 90% of the time it's always set to 1m.
Reinhold said he could grind the r/f cam on the lens to make the focusing
right on, if I wanted to spend the money. 

If I find myself in critical focusing situations, I either use my 21/3.4
S/A, or focus using another lens/body combo, and transfer the distance
reading to the 21/2.8 (only done it twice in 18 months).

BTW, this is what stopped me from having my 24/2.8 'gogglized', I'm not so
confident in Zone focusing the 24 - but I hate having that vulnerable V/F on
top of the body, when you end up with (say) 3 bodies in use.

So, I think the goggles do have some impact on focusing, R/F, cams, and the
opto-mechanical stuff about which I know zero.

Tom A., Sherry are you out there with more and better facts on this?

If this is completely unrelated to the original issue, please test your
flamethrowers against my asbestos suit.

Alistair



- -----Original Message-----
From: Michael Dienert [mailto:MDienert@foq.de]
Sent: Thursday, April 29, 1999 6:33 AM
To: 'leica-users@mejac.palo-alto.ca.us'
Subject: AW: [Leica] New User Question


hello,

my name is michael and i own a m3 and a cl. from my understanding of the
rangefinder mechanism your assuption that the eyes have an effect to the
alignment of the rangefinder must be wrong. in my opinion the reason for
your focussing problems is not the absence of the eyes. please let me
explain it as follows:

the eyes for the 35mm summaron on a m3 convert the 50mm frame to 35mm.
that means the eyes REDUCE the magnification of the viewfinder with a
factor of approx. 1.4. but a reduced rangefinder magnification results
in a reduced effective rangefinder baselength. so with the eyes the
precision of the rangefinder is even DECREASED!!
(check stephen gandy's pages at cameraquest.com). 

that means without the eyes you should be able to focus even better than
with the eyes. the only reason for the eyes is to convert the 50mm frame
to 35mm. this even works with the 21mm super angulon and the 28mm frame
of an m6. there is a design by tom abrahamsson. he uses the summaron
eyes on the super-angulon.

on the other hand, the eyes for the 135mm elmarit increase the
viewfinder magnification by a factor of 1.4 (later1.5) so the 90mm frame
shows the right section of the scene and increases the rangefinder
precision.

i am sure, that your focussing problems are caused by a horizontal
misalignment of your rangefinder. 

but you can adjust the alignment very easy yourself. the lens cam is
sampled by the small metal wheel at the end of the rangefinder lever.
this wheel is attached to the lever with an eccentric screw. by turning
the screw you can change the alignment. point your camera (summaron
attached) to a vertical object far away (tree, antenna mast etc). set
the lens to infinity and check if you have alignment. if not, take of
the lens, turn the eccentric screw and check the alignment again. repeat
this procedure until you have perfect alignment at infinity.

i sucessfully trimmed my cameras this way.

yours

michael


> -----Ursprüngliche Nachricht-----
> Von:	P2CON@aol.com [SMTP:P2CON@aol.com]
> Gesendet am:	Mittwoch, 28. April 1999 21:25
> An:	leica-users@mejac.palo-alto.ca.us
> Betreff:	Re: [Leica] New User Question
> 
> Jem writes, in answer to question on use of 35mm/f3.5 Summaron with
> M6:
> 
> <<SNIP>> << The lens was made in 3 versions.
>  In 1954 for the M3 w/out the eyes, keying the widest frame then
> available, 
> 50mm.
>  
>  In 1956 for the M3, with the eyes, still keying the 50mm frame but
> optically
>  widening it to show 35mm area.
>  In 1958 for the M2 (and therfore the M4, M5 and M6) keying in the
> 35mm frame.
>  
>  If you bought the lens without the eyes and it is obviously designed
> for them
>  (look for the screw holes) then the lens is pretty worthless and you
> need to
>  take it back if possible.
>  If you have the eyes, put them back on.
>  The upshot is that the lens will work well with the M6 providing the
> eyes are
>  on, you will notice a very wide field of view (equivalent to 20mm or
> so) and
>  therefore the 35mm frame will seem small within that, but trust me,
> it is
>  correct. >> <<SNIP>>
> 
> I am the original poster and wish to thank all who responded to my
> question. 
> Lucian and Michael for directions to the Archives, and A.H. Schmidt
> and Jen 
> for direct input to my specific question.  As suggested in Jen's
> answer 
> above, I do have the M3 version (1957 by s/n) with the eyes missing.
> The lens 
> is not totally useless though, as it can be focused using the scale on
> the 
> lens barrel instead of the rangefinder. Actually not a major problem
> for 
> street grab shots. I have put one roll of Elite Chrome
> Select 100 thru it taking two shots of each subject, one using the 
> rangefinder and the second using the lens barrel scale. Subject matter
> was a 
> Clasic Car show on the streets of Seal Beach, CA, and the focus
> distances 
> from about 3 feet to maybe 25 feet.
> Results with the scale focus were nice and sharp, and those using the 
> rangefinder were noticeably out of focus, or at least much softer
> where the 
> DOF was greater.
> 
> After the shoot I gave the lens to a local leica repair specialist to
> clean 
> up the 40 years of haze (actually very slight), and he confirmed the
> focus 
> peculiarity of the lens without the matching eyes. He said that the
> lens 
> could be made to focus without the eyes by carefully re-grinding the
> focus 
> cam to match the rangefinder image. Then of course the lens would not
> work 
> "with eyes". I am going to keep the lens without the eyes and hope
> that 
> someday I will run into some "eyes" that do not have a proper home.
> Until 
> then it will be "grab shots with scale focus".
> 
> Sorry for the long post, and thanks for listening.   Paul Connet