Subash, I can't get it to autofocus with the A400/5.6, but the A200 f4 and A300 f4 work fine for me. I think this is an autofocus with the 1.7 and A300. http://picasaweb.google.com/rf.sullivan/PDML2009#5436368437062520114 Regards, Bob S.
On Wed, Nov 10, 2010 at 10:01 PM, Subash <pdml.l...@gmail.com> wrote: > On Wed, 10 Nov 2010 22:47:46 -0500 > "P. J. Alling" <webstertwenty...@gmail.com> wrote: > >> That combination works very well together. The largest problem is >> achieving focus lock. Pentax doesn't recommend the AF 1.7x being >> used with lenses having a slower maximum aperture than f2.8. This >> results in a maximum aperture equivalent to f4.6. Using it with an >> f4.0 lens gives a maximum aperture of ~f6.7 which is 2/3 of a stop >> slower than the slowest maximum aperture, (f5.6), I've ever seen on >> a Pentax auto focus lens. At those apertures the cameras really >> struggle to focus in even moderately low light conditions. However >> in bright light AF is no real problem and the images are quite sharp. > > that's reassuring to know. i guessed it could be because of the > slower f/4, though the user manual does list a f3.5 zoom... > > thanks, subash > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
