View Full Version : Meaning of

Michael N. Smith
30-Nov-1998, 16:20
What is the significance of the designations used on older Lf lens, of the word series? example: (Tessar series 2a) or (Cooke series 5)

Erik Ryberg
30-Nov-1998, 23:16
Michael, This had me really baffled when I first got into photography and needed to buy a lens. "Series" refers to size filter the thing takes, usually (I think that is the only reference - maybe someone will correct me if I am wrong.) "Tessar" is lens design. Several companies made a tessar. Other designs you will see are optar, raptar, anastigmat, aviar, xenar, angulon and many others. Cooke was a manufacturer- or was it also a formula? Hmm. I am still seeking a comprehensive list of lens formulas/manufacturers that will clearly display the pros and cons of each design. If you find one let me know where it is. Erik Ryberg

Alan Gibson
2-Dec-1998, 06:54
According to "Applied Photographic Optics", Sidney F. Ray, Cooke was a company in York (England), and the Cooke triplet was originally developed by Harold Dennis Taylor (1865-1915) of Cooke. The Tessar design came from Paul Rudolph (1858-1935) of Zeiss.

Historical developments of lenses are fascinating, but I doubt that they can provide real guidance to comparative quality.