[LRflex] Re: Z + N = ? OT (maybe)
- From: George Lottermoser <imagist3@xxxxxxx>
- To: leicareflex@xxxxxxxxxxxxx
- Date: Tue, 07 Jun 2011 16:22:30 -0500
On Jun 7, 2011, at 3:45 PM, Richard Ward wrote:
> The problem is composed of those light rays and whether the 'image' they are
> describing are aligned in such a manner that they land in the photo detector
> wells in a way that they are accurately recorded or not is utterly divorced
> from whether the subject is a f1.2 portrait of a fair lass or a f16 group
> shot of a hundred rowdy school kids or a carefully aligned copy photo of the
> Mona Lisa.
> The optical mechanism at work at the sensor level here is supposed to be
> quite like the one which 'haunts' the move of the Leica M to a Digital
> Platform. When Wide and Ultra-Wide lenses are being used, the light rays are
> being sent to the sensor at angles the photosites in and their associated
> tiny lenses don't work well with.
The issue of casting light to a sensor at severe angles
as encountered with short, non retro-focus wide angle lenses
is IMO quite a different issue Richard.
You were talking about the precise milling of a lens mount being off by what
.01 - .08 mm?
then with a 50 mm lens on a FF sensor
by what amount do you suppose the angle of light rays has changed across the
sensor?
(And some of those light rays will actually hit the sensor more squarely
because of a slight milling error)
You can test this yourself.
Take some black tape and tape a lens to your camera.
Tilt it swing it take some shots.
I can only repeat myself here.
Any lens can be tilted and swung
and still perform to specification
assuming you can actually focus the damn thing.
If you can't focus the lens on the sensor
then you're out of luck.
And of all the elements of the system
that can throw off the focus
the lens mount is the very least to be concerned with
for 99% of practical photography.
While the relationship of
the ground glass : the mirror : sensor
is of all and prime importance.
Regards,
George Lottermoser
george@xxxxxxxxxxx
http://www.imagist.com
http://www.imagist.com/blog
http://www.linkedin.com/in/imagist
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