Exactly what lens IS in this Fuji/Bessa?

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John NYC

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The more I use my Bessa III and understand its strength and weaknesses (and how to exploit its weaknesses to make them useful in real world photography), the more impressed I am with this seemingly simple lens.

Is this lens actually a new design from Fuji for this camera? Somehow I doubt it. If not, what is the history of it?
 
My guess is that it is a new design - Fuji did not have a lens with similar specifications on any earlier camera, and given the power of current CAD tools, calculating a Gauss lens from scratch (or rather, from the departmental database) nowadays should be faster and deliver better results than simply rescaling some old design.
 
sevo said:
My guess is that it is a new design - Fuji did not have a lens with similar specifications on any earlier camera, and given the power of current CAD tools, calculating a Gauss lens from scratch (or rather, from the departmental database) nowadays should be faster and deliver better results than simply rescaling some old design.
Click to expand...

It is a very common symmetrical design, double Gauss with the kitted surfaces plane. In Cox's book on photographic optics the lens cross section is numbered S5 and many manufacturers had one or more in their catalog. If that Fuji cross section is correct then the expectation that it would be a Plasmat design is wrong, the two kitted groups should have been at the outside. Fuji has several Plasmats for MF cameras in its catalog. I think the lens as shown is cheaper to fabricate than the Plasmat; kitted lenses smaller than a Plasmat has + the kitted surfaces plane. The last is hardly possible with a Plasmat design. Modern glass + design software could allow better performance than what was possible when this lens design was the most common of the double Gauss versions. The f 3.5 is conservative for this lens type, probably to keep the lens small enough. Rodenstock's Heligon range is entirely based on it, several French manufactuers used it, some early Zeiss Planars, TT&H Panchro versions, Nikkors and more. A Rodenstock Heligon 95mm 2.8 for 6x9 is mentioned.


met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/
 
A follow up on this. I asked myself whether the designers of the modern Plaubel Makina made similar decisions on the lens design. It is f 2.8 so a bit faster and it shows as a bigger lens on that 6x7 camera. Yesterday I found this cross section of it:
http://nikomat.org/priv/camera/mednikkor/makina/makina-e.html
I would call that a hybrid of a Plasmat and a double Gauss. In Cox's book I find one design that resembles it, a Zeiss Planar 80mm f2.8 for 35mm coverage.

met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/
 
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