[Leica] RE; Autofocusing M lenses

[Peter Klein]

In theory it should work just fine. You leave the lens on infinity, and the
adapter does the rest.  The adapter must:

-Interface to the camera's AF electronics such that the camera can tell it
"forward, back, stop").
-Be thin enough to allow infinity focus.
-Contain motors and a mechanism that will rack the lens out sufficiently to
focus the lens to a reasonable close distance. The mechanism must fit in
the adapter. This is easier to do with SLR lens adapters. M lenses have a
shorter back focus distance, and M to mirrorless adapters are quiet short
compared to SLR adapters. Perhaps some of the mechanism could be below the
adapter, or concentric to it.)

The major problems with M lenses on other cameras would still be corner
smearing and color shifts, unless the sensor's Bayer array was designed for
M lenses. And would the autofocus be fast and accurate enough, and would
using the adapter be convenient enough that you wouldn't get fed up with it
quickly?

Personally, I'd love to have an autofocus M that also did RF focusing.  But
as Larry mentions, it would have to be worth someone's while to
manufacture. Most manufacturers have already passed on making their own
rangefinder mechanism. Leica seems to be willing to make RF cameras along
traditional M lines, but not to do anything radical with them.  But what
about something entirely new by a third party--an AF camera that also did
some sort of visual rangefinder simulation in an EVF, and was designed to
take M lenses. Ideally, the version for M lenses would have a Bayer array
with microlens offsets licensed from Leica.  The SLR lens version would
have a more conventional sensor.

All technically possible. The big question is whether there are enough
legacy(*) lens fans, and in particular M lens fans, to make such a camera
commercially viable.

--Peter, who actually dislikes the word "legacy."

On Thu, Feb 11, 2016 at 4:22 PM, Larry Zeitlin via LUG <lug at leica-users.org>
wrote:

> About 40 years ago, give or take a decade, a precision camera make,
> probably Zeiss. marketed a camera in which the focus was adjusted by moving
> the film plane. This simplified lenses but had the downsides of increased
> expense for the camera body and the difficulty of providing enough motion
> for long focus lenses. The idea was abandoned after a few years but I
> believe that with modern electronics it could provide automatic focus for M
> lenses. But, of course, there would be little incentive for Leica to adopt
> such a system. Maybe a third party could sell a universal camera which
> would autofocus with all makers lenses.
> Larry Z
>
> + + +
> LUG:
>
> Any idea whether this would actually work or not?
>
>
> http://www.thephoblographer.com/2016/02/11/the-techart-pro-lens-adapter-promises-autofocus-for-leica-m-mount-glass/#.VrywD_krJaQ
>
> Tina
>
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