trondsi
Member
- Joined
- Jun 29, 2015
- Messages
- 454
- Format
- 35mm
Trondsi, go here http://www.largeformatphotography.i...to-look-for-information-on-LF-(mainly)-lenses for links to manufacturers' catalogs and other useful information. The catalogs show lens cross-sections.
Plasmat types are roughly symmetrical, each cell has three elements. From the outside in, a cemented doublet (two elements), an air space, and a singlet (the third element). For some reason we tend to refer to Fujinon Ws as plasmats even though some (six elements in six groups) aren't. The typical LF plasmat is f/5.6 or slower.
The Xenotar you're thinking of is a five element double Gauss type. It is a variant of the six element double Gauss type, sometimes called planar type. Roughly symmetrical, each cell has three elements. From the outside in, a single, an air space, and a cemented doublet. Five element double Gauss types (Xenotars, some Zeiss Oberkochen Planars) replace one of the cemented doublets with a singlet. All are good lenses, but with less coverage than the typical plasmat of the same focal length. Six element double Gauss types, starting with the TTH Opic and Dallmeyer Super Six are (f/2.0 and f/1.9 respectively) are faster than plasmats. Five elementers are typically f/2.8.
I take it you're dreaming and haven't shopped yet. 135/2.8 Xenotars and Planars are much more expensive than 135/5.6 plasmat types.
That is correct. I'm a little low on cash right now, but I will be looking for a new lens for the Crown Graphic in the near future. Any specific recommendations for plasmat-type lenses?