Archived posting to the Leica Users Group, 2012/07/21

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Subject: [Leica] Some technical speculations re: rangefinder
From: kanner at acm.org (Herbert Kanner)
Date: Sat, 21 Jul 2012 20:23:21 -0700
References: <CAF8hL-EMSebH=YGfXU=qpuVyMbZxGjfH9cebK-BNVAS6oCMMkQ@mail.gmail.com> <p06240809cc308b2b92c9@192.168.1.103> <CAF8hL-H0Pne4ev8Q4Du2WD+8tGafOVa2YQ4r-m7qtzda+iBK-Q@mail.gmail.com>

Wow! That was something I was not aware of and had me going for a 
while. Then I started thinking about it like the physicist I once 
was. I said, ok, when you get closer, the lens has to move away from 
the sensor/film. Now think about a pinhole, which could be thought of 
as an highly stopped down lens. As the pinhole moves away from the 
film/sensor, the angle subtended by same becomes smaller. So the 
frame lines in the viewfinder should get closer to each other, making 
a smaller rectangle.

Good to be forced to think once in a while.

Herb



>Thanks Herb. I am aware of that. I am referring to the size of the
>framelines. As you get closer, the coverage should get smaller.
>
>On Sat, Jul 21, 2012 at 9:39 AM, Herbert Kanner <kanner at acm.org> wrote:
>
>  > Richard,
>  >
>  > We already have parallax adjustment based on focusing distance on all M?
>  > cameras. Hold your camera very steady and watch the frame lines as you
>  > focus from minimum distance to infinity. If it isn't visible on those 
> 28mm
>  > lines, shift the control to 35mm or longer or put in a longer lens.
>  >
>  > Regards,
>  >
>  > Herb
>  >
>  >
>  >
>  >
>  >  Speculating on an ideal optical rangefinder system (i.e. something that
>  >> retains the Leica M DNA and yet improves on the 1950 state of the art 
> M3),
>  >> what if a rangefinder has the following features:
>  >>
>  >> - LED projected framelines. This removes the clutter, solves the
>  >> visibility
>  >> issue, and
>  >>
>  >> - changeable rangefinder magnification - what if the rangefinder has 
> 0.58x
>  >> to 1.2x mag builtin (may be in 4 steps: 0.58x, 0.72x, 0.9x and 1.2x or
>  >> something similar)? This would allow more precise focusing from the 
> wide
>  >> to
>  >> tele. This will leverage the existing frame line trigger and 6 bit 
> coding
>  >> system of course so this would be automatic
>  >>
>  >> - parallax adjustment based on focusing distance
>  >>
>  >> We know LED framelines can be done. The M9 Titanium has it.
>  >>
>  >> The XPan has 2 magnifications: one for the 45mm lens and one for the 
> 90mm
>  >> lens. I have no idea how difficult it is to insert multiple mag piece 
> as
>  >> needed. Anyone knows?
>  >>
>  >> The cam position should also give good indication of the focusing 
> distance
>  >> too, along with the lens info, so #3 is technically feasible too.
>  >>
>  >> Chances are Leica nor anyone else would really spend the resource to
>  >> develop something like these, since a CMOS/Liveview is so much 
> "simpler,"
>  >> but would it be nice to have such a system?
>  >>
>  >> --
>  >> // richard
><http://www.richardmanphoto.**com<http://www.richardmanphoto.com>
>  >> >
>  >>
>  >> ______________________________**_________________
>  >> Leica Users Group.
>  >> See
>http://leica-users.org/**mailman/listinfo/lug<http://leica-users.org/mailman/listinfo/lug>for
> 
>
>more information
>  >>
>  >
>  > --
>  > Herbert Kanner
>  > kanner at acm.org
>  > 650-326-8204
>  >
>  > Question authority and the authorities will question you.
>  >
>  >
>  > ______________________________**_________________
>  > Leica Users Group.
>  > See
>http://leica-users.org/**mailman/listinfo/lug<http://leica-users.org/mailman/listinfo/lug>for
> 
>
>more information
>  >
>
>
>
>--
>// richard <http://www.richardmanphoto.com>
>
>_______________________________________________
>Leica Users Group.
>See http://leica-users.org/mailman/listinfo/lug for more information

-- 
Herbert Kanner
kanner at acm.org
650-326-8204

Question authority and the authorities will question you.


In reply to: Message from richard at richardmanphoto.com (Richard Man) ([Leica] Some technical speculations re: rangefinder)
Message from richard at richardmanphoto.com (Richard Man) ([Leica] Some technical speculations re: rangefinder)