Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-19-2012, 06:00 PM   #1
New Member




Join Date: Dec 2010
Location: Charlotte, NC
Posts: 11
Pentax-DA 35mm F2.4 AL autofocus not working

I just purchased the 35mm F2.4 AL lens 2nd hand and it appears that the autofocus is not functioning as it should. Camera is a k100D. My other lenses all A/F fine, so was just wondering if there was anything I could check before I return it. I can manual focus it (sorta, it's pretty stiff) and if i turn the focus ring while the lens is off the camera, i do see the AF screw drive pin turning. When I hold the shutter, i do hear it twitch, but that's it.


Last edited by mr_white; 01-19-2012 at 06:16 PM.
01-19-2012, 06:16 PM   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,128
Is the manual focus stiff even when you put the camera in manual focus mode? If so, then AF mechanism is probably broken, though it should be fixable. You might even be able to do it yourself, but if you have the option of returning the lens, do so and get a new one.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

01-19-2012, 07:24 PM   #3
Veteran Member
VisualDarkness's Avatar

Join Date: Nov 2011
Location: Uppsala, Sweden
Photos: Gallery
Posts: 4,441
Can you turn the AF screw-drive a couple of times? Once a lens got stuck for my and my brother turned the screw to make it work again.
01-20-2012, 03:40 PM   #4
New Member




Join Date: Dec 2010
Location: Charlotte, NC
Posts: 11
Original Poster
i can see the screw turn if i turn the focusing ring. it seems to spin freely, but i guess whatever controls it in the lens isnt working. was just hoping for a possible somewhat easier/faster solution than returning it, waiting for a refund, then buying another.

01-20-2012, 03:48 PM   #5
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,128
That sounds like normal operation to me. Perhaps the lens wasn't mounted correctly? With the screwdrive AF system, there's nothing in the lens apart from some gears that link everything together.

Does the focus setting on the lens change if you turn the axle on it?

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

01-20-2012, 03:52 PM   #6
New Member




Join Date: Dec 2010
Location: Charlotte, NC
Posts: 11
Original Poster
sorry im pretty amateur with your terms

can you explain what you mean by focus setting and turn the axle?

and is it possible to mount it wrong?
01-20-2012, 04:01 PM   #7
New Member




Join Date: Dec 2010
Location: Charlotte, NC
Posts: 11
Original Poster
if you mean does the rear element move forward and back when i turn the focus ring, then yes.

when i put the lens on the body, if the focus is all the way out, and i point it at something far away, the focus ring will come in about half way then it stops. if i half press the shutter for autofocus, i can hear the motor click, and feel the focus ring twitch, but it does not move in or out. I said the focus ring feels stiff, and what i mean by that is when you turn it, it doesnt feel as fluid as my other lenses. It moves, but not as fluidly/smoothly as say the kit lens. I had read that manual focusing with this lens was difficult, didnt know if that was the reason or if it's something else.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
autofocus, camera, f2.4, focus, lens, pentax help, pentax-da 35mm f2.4
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K-5 + 18-55mm Wr - Autofocus not working?? hknymz Pentax K-5 11 02-29-2012 04:50 AM
Grrr...autofocus on k-x not working rachcobb Troubleshooting and Beginner Help 9 01-10-2012 09:29 AM
For Sale - Sold: Pentax smc FA 35mm f2 Autofocus AF Fleafly Sold Items 2 12-24-2011 06:11 PM
Do 35mm SLR lenses autofocus on Pentax DSLRs (K-x) ? photoleet Pentax SLR Lens Discussion 3 08-08-2011 04:41 PM
35mm Autofocus:Affordable options? Jetsam1 Pentax SLR Lens Discussion 4 03-16-2011 07:56 AM



All times are GMT -7. The time now is 08:24 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top