> Hi Lon, > I can think of this explanation: > > difference of 1/2 stop at f/11 - 22 is so small in absolute > physical dimensions that they did feel that making halfstops > there would not be repeatable enough due to mechanical > nature of the aperture mechanism. f/16 and f/13.5 are just > 0.5mm diameter difference! >
I don't think this is the case. My SMC 24 f/2.8 has a 1/2 stop at f/13. The aperture openning is tiny, but the mechanism seems quite precise. -Scott
