Originally posted by RiceHigh
My guess is the SDM *might* have less inertia and that it *might* stop faster than screw driven motor for the lens during focusing but my experience with MZ-S and those SDM lens on K10D is that both control can be achieved to be very good if the AF system is good enough. In the case of SDM on K10D, I just found the motor is just felt to be quite a bit "difficult" to turn and focus the lens fast enough and at least the MZ-S is much faster and start/accelerate much faster and stop also faster and more precisely with less hunting.
MZ-S is
much faster? Hmm, I've had two MZ-S, and three K10D, but I haven't seen that MZ-S is MUCH faster than the K10D as far as AF goes. And I've tested several DA* zoom lenses on three different K10D cameras, the K10D can lock to a target from infinity to close target within half a second (less than 1sec in low but not dark condition) with either the DA*16-50 or DA*50-135 lens mounted, how MUCH faster the MZ-S can be? 0 second?
I think this time it's your title of this thread that puts some people off:
K10D+SDM=(much) Slower AF Speed? Many users have confirmed that the two release SDM lenses don't seem to help with much faster AF speed, but definitely not MUCH slower!
Thought I shouldn't reply this thread, but just like some said above, you can't ignore some lies all the time.
Besides, why you always quote something from your blog instead of directly link to the original source? Playing the peacock? Sorry if this offends you.
To the other friends here, cheer up guys. SDM is great, it's a big step forward from previous screw driven lenses. I'm sure Pentax would get it improved in the future. BUT even at this stage, it definitely ISN'T much slower