[Leica] BESSA R3A or M7

[richard-lists at imagecraft.com (Richard)]

At 03:34 AM 1/8/2005, Bill Marshall wrote:
>...
>
>Zeiss emphasizes the greater precision of focusing that they have achieved 
>with this new camera system by virtue of its long effective base length & 
>this minimization of focus shift - an issue highlighted by the indubitable 
>Mr. Puts in his review of the Noctilux. If Zeiss has accomplished this, it 
>will be a significant benefit especially for photographers who work at or 
>close to full aperture on fast lenses.

I know nothing about lens and camera design, so several questions come to 
my mind:
- focus accuracy - it can't solely be based on the RF baselength, can it? 
The RF mechanism must be incredibly precise to translate the small amount 
of helical movement into RF patch matching? Also, how about the helical 
tolerances of the lens themselves. We know the CV lens are "good enough" 
and they have the know how to make a 35/1.2 lens, but are there any 
potential issues there?

- focus shift. I believe Mr. Puts mentions that ONLY the Noctilux has the 
problem? So they are solving an non issue as they are not putting out a 
Noct. competitor!!! In other words, marketing hype.


>In what is, I assume, an unrelated comment of marketing promotion, Zeiss 
>says that its "bright & sharp rangefinder field . . . does not shift or 
>wander when focusing." I only mention it here because it is another 
>mention of "shift" in relation to focus.

The only RF field shift that I have seen is from the R-D1, which is based 
on the Cosina Bessa. Then again, the only RD I have used are the M6/M7 and 
the R-D1, so definitely not from much experience here. Again though, this 
sounds like more marketing hype than anything else.

>Cheers,
>Bill
>
>
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// richard (This email is for mailing lists. To reach me directly, please 
use richard at imagecraft.com)