Kit lens, but no AF

helmut · 08-15-2011, 06:09 AM

I have recently purchased a Pentax K-7 plus 2 kit lenses, the SMC-DA 18-55, the SMC-DA 50-200 from e-Bay. Whilst the 50-200 works perfectly fine, with the short zoom 18-55 the camera asks for the focal length and AF is not available. It would seem that the K-7 does not recognise the lens and therefore (?) does not engage the slotted drive mechanism for AF.
As the aperture is set correctly and the lens does have a focussing ring, this does not really bother me. However, without a Katz-Eye (or whatever) gadget, focussing through the viewfinder is a bit awkward.
Is there a simple "repair" possible? I have carefully cleaned the contacts with alcohol and checked that the AF screw is not stuck, but to no avail. The lens should still be covered by warranty, so I could take it to a local Pentax retailer (there IS one in Vienna / Austria).
Thank you

mannesty · 08-15-2011, 06:20 AM

I think you've probably answered your own question. If it's in warranty, take it to a dealer because it clearly is not working as it should. You might even get lucky, and they might just replace the faulty item, which I think is probably the lens.

JeffJS · 08-15-2011, 06:23 AM

When your focus selector is set to one of the AF modes (AF-C or AF-S) the screw drive should engage whether the camera recognizes the lens or not. It may not turn but the mechanical connection should still be there. If you've cleaned the contacts, the 50-200 works, and you're certain the 18-55 is completely locked on, I would tend to blame the lens. You say there is a vendor in your area so I would take the camera and the lens and see what they say. You could also try a few Other AF lenses while you are there to verify further, it is not the camera. Did you buy this outfit New or Used?

ultraviolet · 08-15-2011, 06:24 AM

Originally posted by helmut

the camera asks for the focal length and AF is not available.

Cleaning the electric contacts on the lens might cure the problem.

mannesty · 08-15-2011, 08:33 AM

Originally posted by ultraviolet

Cleaning the electric contacts on the lens might cure the problem.

You obviously missed the "I have carefully cleaned the contacts with alcohol " part of the original post.

RioRico · 08-15-2011, 08:37 AM

The problem you describe is usually caused either by the lens not being fully mounted, or by dirty or faulty contacts, or by internal factors (bad circuitry or whatever). Since you've dealt with the external possibilities, it's likely the problem is within the lens. Send it back.

MysteryOnion · 08-15-2011, 08:51 AM

Under warranty... yes, take it in. Some AF clutches may not be attached right and will require the reattach and thread-lock of vital screws. Better to take it in for a look than to have screws possibly banging around inside and causing more damage. Please let us know of the results, good luck.

helmut · 08-15-2011, 09:06 AM

Thank you for the replies.
I will take the camera plus lens(es) to the local Pentax rep for a diagnosis, a therapy and (possibly) for a lens transplant.
Greetings from Vienna.

08-15-2011, 06:09 AM	#1
helmut New Member Join Date: May 2011 Location: Vienna / Europe Photos: Gallery Posts: 3	Kit lens, but no AF I have recently purchased a Pentax K-7 plus 2 kit lenses, the SMC-DA 18-55, the SMC-DA 50-200 from e-Bay. Whilst the 50-200 works perfectly fine, with the short zoom 18-55 the camera asks for the focal length and AF is not available. It would seem that the K-7 does not recognise the lens and therefore (?) does not engage the slotted drive mechanism for AF. As the aperture is set correctly and the lens does have a focussing ring, this does not really bother me. However, without a Katz-Eye (or whatever) gadget, focussing through the viewfinder is a bit awkward. Is there a simple "repair" possible? I have carefully cleaned the contacts with alcohol and checked that the AF screw is not stuck, but to no avail. The lens should still be covered by warranty, so I could take it to a local Pentax retailer (there IS one in Vienna / Austria). Thank you

08-15-2011, 08:37 AM	#6
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	The problem you describe is usually caused either by the lens not being fully mounted, or by dirty or faulty contacts, or by internal factors (bad circuitry or whatever). Since you've dealt with the external possibilities, it's likely the problem is within the lens. Send it back. Last edited by RioRico; 08-15-2011 at 10:02 AM.

08-15-2011, 09:06 AM	#8
helmut New Member Join Date: May 2011 Location: Vienna / Europe Photos: Gallery Posts: 3 Original Poster	Thank you Thank you for the replies. I will take the camera plus lens(es) to the local Pentax rep for a diagnosis, a therapy and (possibly) for a lens transplant. Greetings from Vienna.

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08-15-2011, 06:20 AM	#2
mannesty Senior Member Join Date: Mar 2008 Location: Totana - Murcia (Spain) Posts: 127	I think you've probably answered your own question. If it's in warranty, take it to a dealer because it clearly is not working as it should. You might even get lucky, and they might just replace the faulty item, which I think is probably the lens.

08-15-2011, 06:23 AM	#3
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	When your focus selector is set to one of the AF modes (AF-C or AF-S) the screw drive should engage whether the camera recognizes the lens or not. It may not turn but the mechanical connection should still be there. If you've cleaned the contacts, the 50-200 works, and you're certain the 18-55 is completely locked on, I would tend to blame the lens. You say there is a vendor in your area so I would take the camera and the lens and see what they say. You could also try a few Other AF lenses while you are there to verify further, it is not the camera. Did you buy this outfit New or Used?

08-15-2011, 06:24 AM	#4
ultraviolet Pentaxian Join Date: May 2010 Photos: Albums Posts: 687	Originally posted by helmut the camera asks for the focal length and AF is not available. Cleaning the electric contacts on the lens might cure the problem.

08-15-2011, 08:33 AM	#5
mannesty Senior Member Join Date: Mar 2008 Location: Totana - Murcia (Spain) Posts: 127	Originally posted by ultraviolet Cleaning the electric contacts on the lens might cure the problem. You obviously missed the "*I have carefully cleaned the contacts with alcohol* " part of the original post.

08-15-2011, 08:51 AM	#7
MysteryOnion Giveaway winner! Join Date: Dec 2007 Location: beantown Photos: Albums Posts: 944	Under warranty... yes, take it in. Some AF clutches may not be attached right and will require the reattach and thread-lock of vital screws. Better to take it in for a look than to have screws possibly banging around inside and causing more damage. Please let us know of the results, good luck.