Originally posted by newpentaxman a while back i purshased an sf1 on ebay and it's a sight to behold. i then purchased a quantaray 28-90 mm auto focus lens because i didn't have any of those.it's brand new and when i installed it on the camera it won't auto focus. it'will manual focus just fine. because of the age of the camera do i have to get aparticular lens? i've checked my settings and their right on.( i was able to get a manual). according to the box it works on all of the other auto focus film cameras.
what am i doing wrong?
Just to be clear, and I don't mean to be insulting, but are you sure that the lens is designed for Pentax cameras? Quantaray certainly made a 28-90mm AF zoom for Pentax. I have one. But they also made identical lenses for other mounts, such as Nikon and Canon.
A Nikon-mount lens will fit on a Pentax camera, but none of the electrical or mechanical connections will work. This could explain why your lens won't autofocus.
Any k-mount AF lens should work on an SF1, except for the newest SDM (in lens focus motor) lenses.
BTW, the SF1 is a nice camera. I've got one. In fact, that's the camera I use my Quantaray 28-90mm zoom on. The camera is built like a tank.
Check out the photos of Pentax lens mounts in the Beginner's forum:
https://www.pentaxforums.com/forums/pentax-beginners-corner-q/87608-photos-lens-mounts.html
Scroll down to the KAF mount lens. Note the AF drive screw at about four o'clock in that photo. It looks like a flat-blade screw head. The rest of the screws, that actually hold the lens together, are Phillips screws. Does yours have one of these? With the lens off the camera, turn the focus ring. The drive screw should turn as you turn the focus ring. If it doesn't something is broken inside the lens.
Last edited by noblepa; 10-21-2010 at 06:56 AM.