RE: [Leica] The real information about a Digital M camera

["B. D. Colen" <bdcolen@earthlink.net>]

And why can't the sensor be set far enough back from the rear of the lens to
eliminate this problem? And if the problem with having the sensor in the
normal position is that there is degradation of the image at the edges,
doesn't this simply require the same kind of focal length multiplication we
see with most digital SLRs? i.e., a 35 1.4 Summliux would be, say, a 52.5
1.4 lens using the more central area of the 35 mm lens. Of course this would
require some sort of viewfinder masking, but that's hardly an insurmountable
problem.

I acknowledge that my knowledge of optics and optical issues is more than a
little limited. But I wonder if what is really at issue here is the Leica
engineers believing that to produce a digital M they MUST produce a camera
that fully utilizes the entire area of the current lenses...this may
definitely be a time and issue for compromise, in order to get a digital M
going before many M users stick their M equipment in the closet and go to
digital equipment produced by other manufacturers.

I know, THAT will NEVER happen...at least not until sparrows fly....;-)

- -----Original Message-----
From: owner-leica-users@mejac.palo-alto.ca.us
[mailto:owner-leica-users@mejac.palo-alto.ca.us]On Behalf Of Sal
DiMarco,Jr.
Sent: Wednesday, May 01, 2002 8:03 AM
To: LUG >for posts
Subject: [Leica] The real information about a Digital M camera


Luggers,
    Below, is the OFFICIAL Leica AG explanation as to why a digital M camera
is not possible at this time.
    They are looking into the problem and hopefully eventually find a
solution.
    Please read it.
Happy Snaps,
Sal DiMarco, Jr.
Philadelphia, PA
Web Site: http://members.fcc.net/sal.dimarcojr


Forwarded message...

Thank you for your e-mail regarding digital LEICA M or R solutions.

First of all, we agree with you that a digital M or R camera would make
sense, because you (the customer) could use your current lenses for the new
system. On the other hand we (the manufacturer) could sell the new product
into an existing consumer base. Because of these reasons, this idea was
subject to intensive research at Leica. As a result we must say, that a
digital M camera is not possible with the current CCD or CMOS technology.
Let me try to explain:

One great advantage of the M camera system is that there is no mirror
between film/shutter and the rear lens element. This makes the lenses very
compact and at the same time very fast. Due to that fact the Light rays hit
the film in a flat angle. On a SLR lens, there is more space between rear
lens element and the film/shutter to accommodate the mirror, the light rays
hit the film in a rectangular or almost rectangular (telecentric) way.

If you use film, there is no difference in performance. If a digital sensor
is employed instead of film, there is a difference:
1. To protect the sensor, a protection glass and filters (anti aliasing, IR)
in front of the Sensor will make an additional and unwanted refraction, if
the light rays will fall on the sensor in a non-rectangular way. this is
destroying the optical performance of the lens. (still good performance in
the center of the image, bad in the edges).
2. To increase the sensibility (speed) of the sensor, the pixels have to
have microlenses to collect more light. Again, if  the light rays will fall
on the film in a non-rectangular way, no or less light will fall on the
pixels at the corners of the image. This will cause a vignetting (dark
corners).

These are major effects which will give the whole system a poor performance.
For these and other reasons, we had to give up the idea at the actual time.
As soon as new technology is available on the sensor side, Leica will
continue the efforts for a digital M-Camera.

The above mentioned problems are less difficult with SLR lenses. The
distance between film/shutter and rear lens element has to be larger because
of the mirror, the light rays are almost telecentric and can therefore be
used for digital. Possibilites for a digital R-Camera are under study at the
moment.



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