jlw
Rangefinder camera pedant
Sonnar2 said:Evidently there is some front-focussing at close distance.
Some of this effect may be due to focus shift, common in older high-speed lenses. The focus plane would change slightly as the lens was stopped down, so the manufacturer would have to calibrate the lens based on a best guess as to whether the user was really going to shoot with it at full aperture, or usually would stop it down a bit. I have no idea what Canon's guess was, but this illustrates the difficulty lens designers faced in the old days...
These hype lenses are a class of it's own. Maybe the 1.5/75 Biotar is the only comfortable "user" lens in this class... but then the Exakta Varex isn't...
The LTM version of the 75/1.5 Biotar certainly isn't what most people would consider a comfortable "user" lens -- only about three are known to exist!