[Leica] Leica lenses on Sony A7

[roark.paul at gmail.com (Paul Roark)]

Frank Dernie <Frank.Dernie at btinternet.com> wrote:

> ...

Two things seem evident to me here, please correct me if I have missed
> something.
> 1. The steep angle through the IR filter will always lead to colour shifts
> in some lenses which will always need to be software corrected.


Have you ever heard a good explanation for the fact that the color is
asymmetrical?  That is, if it were just the longer path the light takes
through the filter at a steep angle, why is one side of the frame different
than the other?  I think there must be some interaction with the Bayer
filter.



> 2. These offset microlenses can only be optimum for one exit pupil
> distance, ...


I think I've read that the Sony a7R is optimized for more wide angle lenses
than the plain a7.  The a7 is probably targeted at the zoom lenses and
50mm.  The a7r we usually see with the 35mm on it.

I think I also read that the M 240 microlenses are not as "wide angle" as
the M9.  Some speculation was that Leica was looking for a body for the R
optics.

 ...

>  I guess the light fall off and colour shift will always be there and will
> be different for each lens design (and only loosely related to focal
> length). The extent to which it can be software corrected will probably
> continue to be developed.


At least at the present state of technology, I assume this is the case
also.  I'm hoping the post-processing software can do the job as well as
the in-camera so that we'll be able to correct optics that are not from the
body manufacturer.

I assume Sony sees its expertise as electronics, not optics.  As such, they
may actually facilitate an open and flexible software correction method so
that they can more easily penetrate the existing "fiefdoms" of the long
established camera manufacturers.  This might be the exact opposite of
outfits like Canon that want to leverage off their installed base of
optics.  I obviously want a totally open system that separates the camera
(digital film) from the optics.  I suspect only Sony has the courage to
think they can win the "digital film" race in such a market structure.



> Some lenses will probably never be all that good on a digital sensor.
>

The worst will probably be my Zeiss 21mm Biogon.  I'll be seeing if, in
B&W, it makes any difference.  Of the optics I have, the best compromise
between retrofocus issues and quality is my 24mm Elmar-M f/3.8 ASPH.   When
I get the Sony body that one will, for sure, be tested on it.  Some early
beta tester said the Zeiss 18mm ZM looked OK in the minimal testing these
pre-production guys could do.  I have one of those also, and it's a dog
compared to the Leica 24.

Paul
www.PaulRoark.com