Biogon == Super-Angulon? (Wikipedia says yes)

[arne_croell]

For anybody interested, the original patent by Rusinov/Roosinov/Roossinov has the US patent no. 2,516,724. You can look it up by inserting the patent no.into their search page:

 

http://patft.uspto.gov/netahtml/PTO/srchnum.htm

 

Since these are old patents,it is only displayed as an image, and one needs Quicktime and ActiveX to view it.

 

It is interesting to note that the outer negative menisci of the original patent are deeply curved not only on the inside but also on the outside, much more than the Biogon, Super-Angulon or any of its successors. I assume the main reason would be cost, as these would be very expensive to produce, requiring a large amount of glass to start with, and the removal of a large portion of it in essentially a one-off process for each surface. The Soviet name for this lens type was "Russar"; some of those were made as a civilian 20mm lens for Leica screw mount, but larger versions have apparently only been made for military and mapping purposes. They show up occasionally at auction. Kingslake mentions that Bertele's patents are valid only for lenses with more than one negative meniscus at each side, since 2 single menisci were covered by Roossinov. I wonder if the S.-Angulon falls under the Roossinov patent.

 

As mentioned above, the first lens to use the Biogon name was a very different beast, a 35mm lens for the Contax based on the Sonnar design.