Re: Evidence of a Contax/Leica partnership?

[Kari Eloranta <kve@dopey.hut.fi>]

Martin Tai wrote:

>On the contrary, the only way to get best optical performance
>is UNIT FOCUSING, ie,  move the lens as a whole. The internal focusing

I'm quite sure this is false. For example macros are specialized
designs for short distances that can be outperformed at infinity.
And obviously viceversa. Macros don't exist only because some people
like to get real close, like two inches. Their imageplane flatness etc.
characteristics etc. are already superior at half a meter which is
within the distance scale of a SLR normal lens. If your argument would
be true, a good, fixed, optical formula would work uniformly well at
all distances (that the lens focuses) which is not true.

I'm not saying that the Contax design is bad, not at all. In particular
it allows the user to switch off the AF and do the focusing manually
with floating elements AND with a tight lens. But to me it seems that
this type of AF in actual use sacrifices some of the optical potential
of the lens. 

Regards,

Kari Eloranta