well a slow lens with overall thin thickness it can be shorter, but if you measure most 50mm faster lenses are slightly retrofocus because their optical centers are more than 5mm out from the flange (flange is 45.5mm from the film plane on M42 and K mount ). JCO
-----Original Message----- From: Andre Langevin [mailto:[EMAIL PROTECTED] Sent: Wednesday, December 01, 2004 5:18 PM To: [EMAIL PROTECTED] Subject: RE: OT: Odd Focal Length >2. 58mm was minimum focal length possible without having >to resort to a retrofocus optical design. > >JCO Not sure I understand... Much shorter lenses were produced without a retrofocus design, for example the Tessar lenses, up to 40mm. Andre
