Shel, answering what I can:
"* Would a shorter focus throw be an indicator of a faster
focusing lens?"
I think this is a big part of the reason why short focus throw
was designed.
"* Are there any Pentax lenses, and maybe even third party
lenses, that are noted for poor autofocus performance, which are
they, and in what areas do they perform poorly?"
There are some reports of pre-digital Sigma lenses not
autofocusing accurately on Pentax DSLRs. I'm not sure which
lenses. Sigma often seems to have such problems. But when such a
problem comes up, they often put a new chip in the lens for free.
Pentax's current DSLRs all autofocus relatively slowly in lower
light levels. The forthcoming D+ may improve that, we hope.
Joe
