Dear Paolo
> 24mm f 2.8 AI vs. 24mm f 2.8 AIS: different focusing rings
This was a common change for the wide angle lenses from AI to AIS in 1982.
This should make it easier to focus, as you usually have a wide depth of field
range with your 24mm. e.g. you use f11, then everything from infinity to 0.8m is
sharp, if you focus to 1.6m. So you do not need to focus a lot :-)
Tom
P.S: This is a trick how you can win any bet agaist a AF camera. The AF
camera tries to adjust the focus, but you need only focus it to the hyperfocal
distance.
