At 31/03/2007, you wrote: >In '84(?) here in Italy Tutti Fotografi magazine published an MTF >analysis reporting that its best working aperture was 3.4, i.e. full >aperture! So, as Tom was saying, the 180 f:3.4 Apo Telyt was designed >to work in the night, probably for military purposes. It was, indeed, designed, under contract, for the US Navy, who wished to keep it "secret". However, they wrote the contract with E. Leitz (Canada) so badly that there was nothing to prevent Leitz from releasing a consumer version. When released, resolution was specified as only being "limited by available film" !!!! As has been mentioned, the only limitations are close focus, and that is because of the optimization for distance/wide aperture use. Not a bad compromise, at all! Cheers! --- David Young, Logan Lake, CANADA Wildlife Photographs: http://www.telyt.com/ Personal Web-pages: http://www3.telus.net/~telyt ------ Unsubscribe or change to/from Digest Mode at: http://www3.telus.net/~telyt/lrflex.htm Archives are at: //www.freelists.org/archives/leicareflex/