Archived posting to the Leica Users Group, 1999/06/28

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Subject: Re: [Leica] RE: Floating Optics
From: Lucien <lucien@ubi.edu>
Date: Mon, 28 Jun 1999 16:56:02 +0200

Dr.Richard Clompus wrote:
 
> A floating optic is usually one lens or a lens group that changes position
> (forward or backward) as the lens is focussed from distance to near.  It is
> done to improve imaging performance at closer focussing distances and
> usually decreases curvature of field.  This lens design is a recent addition
> to Leica lenses (perhaps in the last eight years).....


Richard,

I think it's more than that. The 24/2,8 is here since 1974.
OK, it's a Minolta design.
;-)

Because of floating element, I don't think we will ever see
an Leica R camera with an AF system 'a la Contax AX'.

With that system you loose the quality improvement.

Most of the Leica R wide angle lenses may suffer with that
AF system:

15/3,5 (1980)- 19/2,8 (1990)- 24/2,8 (1974)- 28/2,8 (1994)-
35/1,4 (1984)

Because with the following lenses also, the optical groups
are not moving altogether, I think there will be a problem too:
 
100/2,8 - 180/2 - 180/2,8 APO - 280/2,8 - 280/4 - 400/2,8 -
APO Module.

Lucien