I would like to collect information in this post about the EF, other than specifications. Specs are available in the online manuals.(canonfd.com) I think this would be interesting and would be searchable in the future for anyone desiring information on the EF. Most search results return EF auto focus information. Please contribute facts with sources and your opinions/comments. Also please provide your serial number, the date code in the film cassette compartment and the type of focusing screen. You can substitute XX for the last digits if you don't want to reveal the complete s/n. This would give a date code to s/n comparison and help approximate the focus screen change. The EF was released to the market in November 1973. (Canon Museum) When did production cease? When did you obtain yours if you purchased it new? Center spot microprism focusing screen. (undated manual) Split-image with microprism ring around it. (09-75 manual) Center spot microprism below s/n 330000 and split-image with microprism ring above s/n 330000. (http://home.comcast.net/~starka/FAQL/CanonFD_faql.htm#Efbodies) This is questionable, see my EF s/n and info below. Can anyone confirm the s/n cutoff? Do you know of any changes during the production period? My s/n 323087,date code P1225, (1975, December) and has a split-image with microprism ring.