[LRflex] R 2x APO Extender Question

I'm looking a another lens plus an extender (I'll confess when/if I buy 
it).

Does anyone know for sure the answers to these two questions about the 
2x APO Extender?

      1.  Will it work on the 70-180 APO?  If so, at an effective 360mm 
(2 x 180mm ), would the aperture be (f4) or 5.6?

      2.  Will it work on the 28-90 Asph?  If so, at an effective 180mm 
( 2x 90mm ), would the aperture be f9 ( 2x f4.5 ) or higher?

Any particular caveats about the 2x APO Extender?  I have read none but 
would appreciate user comments.

Thank you for any information you may be able to offer.


Bob


On Mar 31, 2007, at 11:22, David Young wrote:

At 31/03/2007, you wrote:
> In '84(?) here in Italy Tutti Fotografi magazine published an MTF
> analysis reporting that its best working aperture was 3.4, i.e. full
> aperture! So, as Tom was saying, the 180 f:3.4 Apo Telyt was designed
> to work in the night, probably for military purposes.


It was, indeed, designed, under contract, for the US Navy, who wished
to keep it "secret". However, they wrote the contract with E. Leitz
(Canada) so badly that there was nothing to prevent Leitz from
releasing a consumer version.  When released, resolution was
specified as only being "limited by available film" !!!!

As has been mentioned, the only limitations are close focus, and that
is because of the optimization for distance/wide aperture use.  Not a
bad compromise, at all!

Cheers!
---

David Young,
Logan Lake, CANADA

Wildlife Photographs: http://www.telyt.com/
Personal Web-pages: http://www3.telus.net/~telyt




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