k-x peculiar autofocus issue

johnsl · 01-08-2012, 08:10 AM

Having an issue with my k-x. Recently acquired a 35mm macro limited lens. Autofocus had been fine. Noticed one time putting the lens on that the autofocus motor spun with no apparent change in focus, took the lens off and put it back on and then it worked fine. Since then, haven been shooting more with the kit 18-55 and a 40mm limited without issue. Today put the 35 macro back on and now the autofocus is completely broken - again, the motor spins (loudly and long) but there is no change in the focus. The auto/manual switch is working fine, but it seems like like the motor is just not engaging appropriately. Also, when I switch from the 35 macro to the 40 or the kit lens, the autofocus will do the same thing. If I switch auto-manual-auto or take the lenses on or off a couple times the problems seems to resolve itself. Ideas of where the problem might be? I'm guessing I probably need to send the lens and body in.

Docrwm · 01-08-2012, 08:37 AM

If I am reading this right the problem started with the 35 Macro but the other lenses were fine. After putting the 35 back on the camera you are seeing the problem withall 3 lenses, right?

Hope someone has some specific trick or insight into the 35 Macro but it does sound like a trip for repair is indicated now. Sorry. From the progression you listed it sounds like the 35 Macro may have something wrong with it that has damaged your K-x. I'd probably send it along with the K-x to CRIS.

Philoslothical · 01-08-2012, 10:18 AM

It's also possible that the failure is coincidental with acquiring the 35mm. It sounds like the pin for the screw drive isn't extending properly, so it's not mating with the connection on the lens. Why it would fail, I have no idea, but it sounds like a likely explanation of what is failing.

Docrwm · 01-08-2012, 10:40 AM

Originally posted by Philoslothical

It's also possible that the failure is coincidental with acquiring the 35mm. It sounds like the pin for the screw drive isn't extending properly, so it's not mating with the connection on the lens. Why it would fail, I have no idea, but it sounds like a likely explanation of what is failing.

Of course it could be coincidental but if I were sending my camera into service I'd send the lens as well as it is the most likely culprit other than simple timing and coincidence. If it isn't the lens, no foul as you couldn't use it while the camera is in for repair. However, if it is the lens then sending it could get everything fixed in one trip and not sending it could set you up for a repeat of the damage to the camera.

Adam · 01-08-2012, 11:14 AM

Take a look at the axle on the back of the lens and see if it moves freely and chances the lens's focus. If not, get the lens exchanged.

Philoslothical · 01-08-2012, 11:20 AM

Originally posted by Docrwm

Of course it could be coincidental but if I were sending my camera into service I'd send the lens as well as it is the most likely culprit other than simple timing and coincidence.

Definitely. I'd probably send one of the lenses that had always previously worked, as well. They generally prefer that you send any affected lenses, to simplify testing the problem.

bobpur · 01-08-2012, 12:23 PM

Hi
Try this, after installing the lens give the manual focus ring a twist and see if it engages the camera.
I have a Af doubler that sometimes does that, it is probably just the position that it is in when the lens is removed or a slight
alignment thing, anyways very doubtfull that it is the camera if with the lens off the drive pin is sticking out and spins.

johnsl · 01-08-2012, 12:26 PM

Took it to my local camera shop - the guy there said the mount connectors on the lens looked a little dirty. He tried cleaning them with q tips and a little alcohol, and so far so good. Thanks for all your help and advice!

01-08-2012, 08:10 AM	#1
johnsl New Member Join Date: Sep 2010 Location: Boston area Photos: Gallery Posts: 10	k-x peculiar autofocus issue Having an issue with my k-x. Recently acquired a 35mm macro limited lens. Autofocus had been fine. Noticed one time putting the lens on that the autofocus motor spun with no apparent change in focus, took the lens off and put it back on and then it worked fine. Since then, haven been shooting more with the kit 18-55 and a 40mm limited without issue. Today put the 35 macro back on and now the autofocus is completely broken - again, the motor spins (loudly and long) but there is no change in the focus. The auto/manual switch is working fine, but it seems like like the motor is just not engaging appropriately. Also, when I switch from the 35 macro to the 40 or the kit lens, the autofocus will do the same thing. If I switch auto-manual-auto or take the lenses on or off a couple times the problems seems to resolve itself. Ideas of where the problem might be? I'm guessing I probably need to send the lens and body in.

01-08-2012, 11:14 AM	#5
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Take a look at the axle on the back of the lens and see if it moves freely and chances the lens's focus. If not, get the lens exchanged. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

01-08-2012, 12:26 PM	#8
johnsl New Member Join Date: Sep 2010 Location: Boston area Photos: Gallery Posts: 10 Original Poster	problem solved! Took it to my local camera shop - the guy there said the mount connectors on the lens looked a little dirty. He tried cleaning them with q tips and a little alcohol, and so far so good. Thanks for all your help and advice!

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01-08-2012, 08:37 AM	#2
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	If I am reading this right the problem started with the 35 Macro but the other lenses were fine. After putting the 35 back on the camera you are seeing the problem withall 3 lenses, right? Hope someone has some specific trick or insight into the 35 Macro but it does sound like a trip for repair is indicated now. Sorry. From the progression you listed it sounds like the 35 Macro may have something wrong with it that has damaged your K-x. I'd probably send it along with the K-x to CRIS.

01-08-2012, 10:18 AM	#3
Philoslothical Veteran Member Join Date: May 2011 Posts: 1,889	It's also possible that the failure is coincidental with acquiring the 35mm. It sounds like the pin for the screw drive isn't extending properly, so it's not mating with the connection on the lens. Why it would fail, I have no idea, but it sounds like a likely explanation of what is failing.

01-08-2012, 10:40 AM	#4
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	Originally posted by Philoslothical It's also possible that the failure is coincidental with acquiring the 35mm. It sounds like the pin for the screw drive isn't extending properly, so it's not mating with the connection on the lens. Why it would fail, I have no idea, but it sounds like a likely explanation of what is failing. Of course it could be coincidental but if I were sending my camera into service I'd send the lens as well as it is the most likely culprit other than simple timing and coincidence. If it isn't the lens, no foul as you couldn't use it while the camera is in for repair. However, if it is the lens then sending it could get everything fixed in one trip and not sending it could set you up for a repeat of the damage to the camera.

01-08-2012, 11:20 AM	#6
Philoslothical Veteran Member Join Date: May 2011 Posts: 1,889	Originally posted by Docrwm Of course it could be coincidental but if I were sending my camera into service I'd send the lens as well as it is the most likely culprit other than simple timing and coincidence. Definitely. I'd probably send one of the lenses that had always previously worked, as well. They generally prefer that you send any affected lenses, to simplify testing the problem.

01-08-2012, 12:23 PM	#7
bobpur Inactive Account Join Date: Jul 2010 Photos: Gallery Posts: 328	Hi Try this, after installing the lens give the manual focus ring a twist and see if it engages the camera. I have a Af doubler that sometimes does that, it is probably just the position that it is in when the lens is removed or a slight alignment thing, anyways very doubtfull that it is the camera if with the lens off the drive pin is sticking out and spins.