[Leica] Leitz Focoslide (through the lens focusing and composition, via a sliding device,using 'pod)

[Rich Lahrson <tripspud@wenet.net>]

Hi everyone!

     I'm considering buying a Leitz Focoslide accessory.  I had one
previously, but never used it as I did not have the 'chimney'
magnifier.

     This device is inexpensive and generally available.  I intend
to use it for close-up/copy work with an Elmar style 50mm/3.5 collapsible
lens.  These slow speed normal lenses should perform okay if
stopped down to about f/8.

     What is the 'extension' caused by the Focoslide, in millimeters?
I understand that the collapsible lenses would allow infinity focus,
where exact composition is needed on a tripod.  

     How close can I focus with the 50mm?  What size screwmount
extension rings were made?  What should I be prepared to pay for
extension rings?  Were extension rings available as a 'set' for the
screwmount cameras?

				Thanks!

						Rich