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

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Subject: [Leica] Some technical speculations re: rangefinder
From: hopsternew at gmail.com (Geoff Hopkinson)
Date: Sun, 22 Jul 2012 14:15:36 +1000
References: <CAF8hL-EMSebH=YGfXU=qpuVyMbZxGjfH9cebK-BNVAS6oCMMkQ@mail.gmail.com> <p06240809cc308b2b92c9@192.168.1.103> <CAF8hL-H0Pne4ev8Q4Du2WD+8tGafOVa2YQ4r-m7qtzda+iBK-Q@mail.gmail.com> <p0624080ccc3121a4d6cf@192.168.1.103>

Herb I would add that the M framing of course is only a guide and the
instruction books show approximate error (in frameline widths) at
minimum/maximum distance



Cheers,
Geoff
http://www.pbase.com/hoppyman



On 22 July 2012 13:23, Herbert Kanner <kanner at acm.org> wrote:

> 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<http://www.richardmanphoto.com>
>> >
>>  >> >
>>  >>
>>  >> ______________________________****_________________
>>  >> Leica Users Group.
>>  >> See
>> http://leica-users.org/****mailman/listinfo/lug<http://leica-users.org/**mailman/listinfo/lug>
>> <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>
>> <http://**leica-users.org/mailman/**listinfo/lug<http://leica-users.org/mailman/listinfo/lug>>for
>>
>> more information
>>  >
>>
>>
>>
>> --
>> // 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
>


Replies: Reply from tedgrant at shaw.ca (tedgrant at shaw.ca) ([Leica] Some technical speculations re: rangefinder)
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)