Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-03-2010, 06:49 AM   #1
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
K20D AF not working properly

Just picked up a K20D body with the intention of having an extra body to go with my Kx. Turns out there is something wrong with the AF and I was wondering if anyone else has had this issue.

Basically, on most of my screw driven lenses, when you try to use AF, the lens just cycles very quickly between the two extreme ends of the focus range and never locks on. The weird part is the problem doesn't seem to affect all my lenses the same way. For example, AF seems to work (and lock) perfectly fine with my F28/2.8 but with the F50/1.7 the AF almost never works. AF with other lenses work fine sometimes, and then all of a sudden stops working. I don't know if it's relevant, but the AF of my SDM DA*50-135 seems to work fine with the body.

I guess my question is has anyone else had a similar issue to this and if so, do you have any idea how much it costs to repair it (assuming it is repairable). Short of being able to solve the problem and/or getting it repaired, I guess another option would be to sell the the body (at a steep discount) to someone who might want a second body just for use with MF lenses.

03-03-2010, 08:23 AM   #2
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,157
What are you pointing the camera at when this happens?
03-03-2010, 08:34 AM   #3
Veteran Member
Reportage's Avatar

Join Date: Feb 2009
Photos: Gallery
Posts: 739
Is yours a used K20D....have you reset to original factory settings?
03-03-2010, 09:15 AM   #4
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
Original Poster
QuoteOriginally posted by Wheatfield Quote
What are you pointing the camera at when this happens?
I tried hundreds of shots, all at very high contrast targets. With certain lens the AF was 100%, fast and accurate. With other lenses, it wouldn't lock at all. And it wasn't even like it was getting close and not locking, it would just quickly cycles from each extreme end (of the focus range) to the other.

03-03-2010, 09:16 AM   #5
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
Original Poster
QuoteOriginally posted by Reportage Quote
Is yours a used K20D....have you reset to original factory settings?
It is used. I haven't tried resetting it yet. I will give that a shot when I get home tonight. I check the firmware and it is running the latest version.
03-03-2010, 11:13 AM   #6
Veteran Member
benjikan's Avatar

Join Date: Jan 2007
Location: Paris, France
Photos: Gallery
Posts: 4,312
QuoteOriginally posted by dgaies Quote
Just picked up a K20D body with the intention of having an extra body to go with my Kx. Turns out there is something wrong with the AF and I was wondering if anyone else has had this issue.

Basically, on most of my screw driven lenses, when you try to use AF, the lens just cycles very quickly between the two extreme ends of the focus range and never locks on. The weird part is the problem doesn't seem to affect all my lenses the same way. For example, AF seems to work (and lock) perfectly fine with my F28/2.8 but with the F50/1.7 the AF almost never works. AF with other lenses work fine sometimes, and then all of a sudden stops working. I don't know if it's relevant, but the AF of my SDM DA*50-135 seems to work fine with the body.

I guess my question is has anyone else had a similar issue to this and if so, do you have any idea how much it costs to repair it (assuming it is repairable). Short of being able to solve the problem and/or getting it repaired, I guess another option would be to sell the the body (at a steep discount) to someone who might want a second body just for use with MF lenses.
Good news..I had exactly the same problem with one of my K20D's and they just have to change a small circuit element and it works perfectly now...

I guess that might be considered good news...
03-03-2010, 11:44 AM   #7
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
Original Poster
QuoteOriginally posted by benjikan Quote
Good news..I had exactly the same problem with one of my K20D's and they just have to change a small circuit element and it works perfectly now...

I guess that might be considered good news...
Do you mind me asking about how much they charged you? I'm just wondering if this is closer to a $100 issue or a $300 issue
03-03-2010, 12:49 PM   #8
emr
Guest




My K20D has never done that. However, my K200D has done something similar with different Pentax lenses. Every now and then the camera would pump very quickly back and forth when trying to lock the focus, even on a bright high contrast object. Probably not from one extreme to the other but a shorter range. I sent the camera to the national Pentax service center twice and after the second time they had changed some hardware, after the first one they told they'd done some adjusting. Unfortunately the camera was just the same after both service trips.

Haven't really used it much since that, don't know if it's still the same.

03-03-2010, 01:17 PM   #9
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
Original Poster
QuoteOriginally posted by emr Quote
My K20D has never done that. However, my K200D has done something similar with different Pentax lenses. Every now and then the camera would pump very quickly back and forth when trying to lock the focus, even on a bright high contrast object. Probably not from one extreme to the other but a shorter range. I sent the camera to the national Pentax service center twice and after the second time they had changed some hardware, after the first one they told they'd done some adjusting. Unfortunately the camera was just the same after both service trips.

Haven't really used it much since that, don't know if it's still the same.
Yeah, I'm not 100% sure it goes through the entire range. Whatever it does, it cycles very very quickly back and forth, but it's not the same way AF would "hunt" in low light. Occasionally it actually pegs out at one end and, gets stuck and doesn't go back. It's just very strange that there is no problem at all with certain lenses (haven't been able to create the issue with the F28/2.8) and nearly 100% failure with other lenses (F50/1.7). Other screw driven lenses, like the FA77 and DA21 are hit and miss.

I've never sent anything to Pentax for repair, so I was unsure of what the procedure was and was hoping to get an idea of the potential cost before I sent it off. If it's going to approach the value of the body itself, I probably won't bother.
03-03-2010, 01:19 PM   #10
emr
Guest




Sorry, forgot to mention that mine was "serviced" under warranty, so I have no idea what they would have charged.
03-03-2010, 01:48 PM   #11
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
Original Poster
QuoteOriginally posted by emr Quote
Sorry, forgot to mention that mine was "serviced" under warranty, so I have no idea what they would have charged.
Just had a chance to go on Pentax's website and I see they offer free estimates for out of warranty repairs (obviously I have to pay shipping both ways). Worst case (if the estimate is too high) I'll be out ~$20 in shipping charges.
03-03-2010, 04:49 PM   #12
Veteran Member
benjikan's Avatar

Join Date: Jan 2007
Location: Paris, France
Photos: Gallery
Posts: 4,312
QuoteOriginally posted by dgaies Quote
Do you mind me asking about how much they charged you? I'm just wondering if this is closer to a $100 issue or a $300 issue
Sorry, but they didn't charge me anything. It was one of the camera bodies they gave me when sponsored by them and thus felt obliged to do it for free. However, I kept the piece they sent me that they replaced and will photograph it so you can see how insignificant it was.
03-03-2010, 05:31 PM   #13
Veteran Member
Timtast1c's Avatar

Join Date: Jan 2009
Location: San Francisco, CA
Posts: 330
I had the exact same issue. One day my k20d just decided not to AF properly with my screw drive lenses.

my 16-50, 50-135, and 300 all auto focused properly with the sdm. My 10-17 and my 40 went crazy!

Fortunately it suddenly started to work again. and I havent had problems since. hope it resolves itself!
03-03-2010, 06:13 PM   #14
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
Original Poster
QuoteOriginally posted by benjikan Quote
Sorry, but they didn't charge me anything. It was one of the camera bodies they gave me when sponsored by them and thus felt obliged to do it for free. However, I kept the piece they sent me that they replaced and will photograph it so you can see how insignificant it was.
Thanks, I'd be interested to see the part.

QuoteOriginally posted by iceemn360 Quote
I had the exact same issue. One day my k20d just decided not to AF properly with my screw drive lenses.

my 16-50, 50-135, and 300 all auto focused properly with the sdm. My 10-17 and my 40 went crazy!

Fortunately it suddenly started to work again. and I havent had problems since. hope it resolves itself!
Yeah, my 50-135 still works fine on this K20D body, but at this point none of my screw-driven lenses work (w/AF) at all. The problem actually went from a few lenses to all of them at this point. "Went crazy" is actually a good way to describe what happens... the focus ring just starts moving furiously back and forth and never locks.

I guess now I just need to find someone who only owns SDM lenses and/or manual lenses who wants a great deal on a K20D body
03-08-2010, 01:35 AM   #15
Veteran Member
benjikan's Avatar

Join Date: Jan 2007
Location: Paris, France
Photos: Gallery
Posts: 4,312
QuoteOriginally posted by dgaies Quote
Thanks, I'd be interested to see the part.



Yeah, my 50-135 still works fine on this K20D body, but at this point none of my screw-driven lenses work (w/AF) at all. The problem actually went from a few lenses to all of them at this point. "Went crazy" is actually a good way to describe what happens... the focus ring just starts moving furiously back and forth and never locks.

I guess now I just need to find someone who only owns SDM lenses and/or manual lenses who wants a great deal on a K20D body
Here is the part. The main element is around 1/8th of an inch wide.
Attached Images
 
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!
af, body, camera, dslr, issue, k20d, k20d af, lenses, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
MX - B not working properly pontusadefjord Pentax Film SLR Discussion 3 09-13-2010 11:01 AM
How do I know if my camera is working properly? Aegon Pentax Film SLR Discussion 15 05-16-2010 10:56 AM
Is my 540 working properly? skystreaker Pentax Camera and Field Accessories 1 04-19-2010 07:19 PM
K20D - Not working Rusty27 Pentax DSLR Discussion 10 12-02-2009 06:14 AM
k1000 light meter not working properly sharko Pentax Film SLR Discussion 10 10-26-2008 11:58 AM



All times are GMT -7. The time now is 07:52 PM. | 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