Archived posting to the Leica Users Group, 2003/07/31

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Subject: Re: [Leica] arggghhh... rant at Keeble & Shucat...
From: "A. Lal" <alal@duke.poly.edu>
Date: Fri, 1 Aug 2003 02:14:53 -0400
References: <9EEE5CC6-C3C1-11D7-9B40-003065BAFBD0@jphotog.com> <013101c35778$88679e50$3004ee80@xyo5pncqiheqc4> <3F29F03B.3030001@2image.com>

- ----- Original Message -----
From: "Kevin H" <kevin@2image.com>
To: <leica-users@mejac.palo-alto.ca.us>
Sent: Friday, August 01, 2003 00:44
Subject: Re: [Leica] arggghhh... rant at Keeble & Shucat...


> Taste's Great!
> Less Filling!
>
> Y'all  are arguing about 2 different things:
>

I don't think so. Not as far as I could tell, anyway.

> Distance or focus at the film plane (COC)?
>
> 1.  Rangefinder:  Measures distance.  Doesn't care what lens is on the
> camera, or even if you leave the lens cap on.  Precision remains
> constant for the rangefinder. Feet is feet.
>
Agreed.

> 2.  Focusing system: At the filmplane.  No confusion,  we're measuring
> the COC.  Focusing accuracy is the end result of  the rangefinder system
> or the TTL system.

Would you mind clarifying the remarks above ? The focussing system does not measure COC  By TTL, do you mean SLR ?

>Since a tele is magnifing the rangefinder's
> precision (and magnifying the eye and mechanical errors) -- it becomes
> less accurate at greater focal lengths.  The SLR's precision is a
> function of the viewing f'stop.

No, a tele lens *does not* magnify a RFDR's precision (unless it is the 135/2,8) or errors, that's the whole point. As for the SLR,
as I mentioned in earlier posts, the effective baselength depends on the aperture (and  magnification), not on the f stop.

There are also other factors involved such as the  type of focussing aid used.

> Everybody is 'right'  -- just talking about different things.
>


Regards,
Akhil


> Kev
>
>
> A. Lal wrote:
>
> >
> >Anyway, Eric I'm not sure if you saw my earlier posts, but the main point is this. A rangefinder, such as the one in an M, has a
fixed base and magnification, which sets practical limits to its ability to measure distance. This *DOES NOT* have anything to do
with the lens mounted on the camera.
> >
> >
> >
> >
> >>No, that's not true. The longer the focal length the less accurate a
> >>rangefinder is.
> >>
>
>
> --
> To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html
>
>

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In reply to: Message from Eric Welch <eric@jphotog.com> (Re: [Leica] arggghhh... rant at Keeble & Shucat...)
Message from "A. Lal" <alal@duke.poly.edu> (Re: [Leica] arggghhh... rant at Keeble & Shucat...)
Message from Kevin H <kevin@2image.com> (Re: [Leica] arggghhh... rant at Keeble & Shucat...)