pagpow
Well-known
Which one? THere is a Canon LTM all chrome - looks like Canon "Sonnar" 50/1.5 and there is a later one that looks like Canon 50/1.4 (sort of). Or they are the same optically?
I'm referring to the silver and chrome, listed as either model III or model III here.
http://www.canon.com/camera-museum/camera/lens/s/50-85.html
The all chrome model I, Canon Serenar, may have the same design -- I do not know and cannot tell from the entries, but it is the silver and chrome ones that have been mentioned as having the rep. At least the diaphragm is different, 10 blades for model I vs 9 for models II and III. See Dante Stella and antiquecameras.com.
Perhaps others can speak more knowledgeably about equivalence of model i vs models ii and iii.