Archived posting to the Leica Users Group, 2001/08/16
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At 8:59 AM -0700 8/16/01, Herbert & Lee Kanner wrote:
>I'm familiar with the notion of a pre-set lens for SLR cameras.
>They pre-dated the automatic diaphragm. But what in the world is a
>"pre-set 90 mm Summicron"? I see them advertised in the used
>sections of the B&H and KEH catalogs.
The first generation 90 Summicrons could have their lens heads
removed to be used on Viso II and III with a short focussing mount.
If they were intended for this use, they could be ordered with a
preset diaphragm control to make life easier on the Viso. Usually, if
they were ordered with the preset lens head, they were also ordered
with the short mount only, and a 'long' mount might not be available
to couple them to the M bodies directly. For use on the M directly,
with rangefinder coupling the preset diaphragm was not an advantage,
and could lead to accidental overexposure, as the correct f/stop
might be set, but the stop down ring not turned to close. Just one
more way to screw up. I've only seen the preset lensheads in chrome.
- --
* Henning J. Wulff
/|\ Wulff Photography & Design
/###\ mailto:henningw@archiphoto.com
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