[LargeFormat] Double Protar Lens

[Richard Knoppow]

----- Original Message ----- 
From: "Ole Tjugen" <oftjugen@online.no>
To: "largeformat" <largeformat@f32.net>
Sent: Sunday, August 31, 2003 11:04 AM
Subject: RE: [LargeFormat] Double Protar Lens


> The Zeiss Series VII Protars were sold as
"Satz-anastigmat", so all elements
> are designed for use alone or in combination with another
of either the same
> focal length, or ONE step up or down.
>
> I can't really imagine that the rear lens should be usable
alone, but not the
> front? Or maybe front and rear are the same, so there's no
difference which
> one you use?
>
> Ole
>
  Both Zeiss and B&L catalogues show that you can go 2
steps. The maximum focal length ratio seems to be around
1.5. Speeds are f/6.3, f/7.0, f/7.7.  I am not sure what
happens if larger ratio cells are combined. I've been told
the performance is still good.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com