Pentax K/5 Unrecognised lens

Photos On the Road · 04-24-2014, 01:34 AM

Hi all
My own Pentax K 5 has started not to recognising my kit lens SIGMA 18/50 f/3.5 5.6 DC.
It means, when the lens is mounted on the camera and I switch it on, the camera asks me to insert the lens focal length, instead of directly showing me the chosen program and then allowing me to shoot.
I have tried to clean the electrical contacts both on the lens and on the camera body, but with no result.
Can anybody please help me on solving this issue?

Adam · 04-24-2014, 02:46 AM

Are you seeing any wear or looseness on the camera or lens mount?

Photos On the Road · 04-24-2014, 05:04 AM

No, it's perfect.
Camera and lens never hit the ground or had similar incidents

JohnX · 04-24-2014, 05:28 AM

Not familiar with this lens, but does it have an aperture ring?

Photos On the Road · 04-24-2014, 10:10 AM

No it doesn't have any aperture ring

stevebrot · 04-24-2014, 05:52 PM

Originally posted by Photos On the Road

No it doesn't have any aperture ring

The body is not detecting the "A" contact on the mount. In order for your lens to be detected correctly, there needs to be electrical continuity between the center of the "A" contact and the mount face. This can be tested with an ohmmeter if you have one.

For a contact map see: Features and Operation of the Ka Mount. The "A" contact is labeled "*" in the diagram.

Are you able to check functionality with a different lens?

Steve

Photos On the Road · 04-25-2014, 12:20 AM

Thank you, this is useful.
All other lenses are perfectly functional.
I had the same issue years ago with a sigma 70-300 that was damaged by hitting the ground.
I have also located the A contact. I have a ohmmeter but i am not sure how to use it in this case

stevebrot · 04-25-2014, 01:25 PM

Originally posted by Photos On the Road

Thank you, this is useful.
All other lenses are perfectly functional.
I had the same issue years ago with a sigma 70-300 that was damaged by hitting the ground.
I have also located the A contact. I have a ohmmeter but i am not sure how to use it in this case

Well, there you go. The problem is probably with the lens. Test for continuity (0 resistance) across the center of the lens A contact to the face of the lens mount. If the circuit is not open, the lens will not be recognized as supporting automated aperture control by the body.

Steve

Photos On the Road · 04-25-2014, 01:44 PM

Originally posted by stevebrot

Well, there you go. The problem is probably with the lens. Test for continuity (0 resistance) across the center of the lens A contact to the face of the lens mount. If the circuit is not open, the lens will not be recognized as supporting automated aperture control by the body.

Steve

Thanks a lot.
And provided, is it the lens do you think the only solution is to throw it away and buy a new one or is there a way to fix it? Thank you again.

stevebrot · 04-25-2014, 03:38 PM

Originally posted by Photos On the Road

Thanks a lot.
And provided, is it the lens do you think the only solution is to throw it away and buy a new one or is there a way to fix it? Thank you again.

It may be something as simple as a loose wire or a broken solder joint. I can't say what the cost or effort to fix might be.

Steve

Photos On the Road · 04-26-2014, 04:49 AM

Originally posted by stevebrot

It may be something as simple as a loose wire or a broken solder joint. I can't say what the cost or effort to fix might be.

Steve

Thank you very much for your help.

Giuseppe

04-24-2014, 01:34 AM	#1
Photos On the Road Junior Member Join Date: May 2012 Posts: 34	Pentax K/5 Unrecognised lens Hi all My own Pentax K 5 has started not to recognising my kit lens SIGMA 18/50 f/3.5 5.6 DC. It means, when the lens is mounted on the camera and I switch it on, the camera asks me to insert the lens focal length, instead of directly showing me the chosen program and then allowing me to shoot. I have tried to clean the electrical contacts both on the lens and on the camera body, but with no result. Can anybody please help me on solving this issue?

04-24-2014, 02:46 AM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Are you seeing any wear or looseness on the camera or lens mount? 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:

04-24-2014, 10:10 AM	#5
Photos On the Road Junior Member Join Date: May 2012 Posts: 34 Original Poster	Aperture ring No it doesn't have any aperture ring

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04-24-2014, 05:04 AM	#3
Photos On the Road Junior Member Join Date: May 2012 Posts: 34 Original Poster	No, it's perfect. Camera and lens never hit the ground or had similar incidents

04-24-2014, 05:28 AM	#4
JohnX Pentaxian Join Date: Jul 2009 Location: London Posts: 1,116	Not familiar with this lens, but does it have an aperture ring?

04-24-2014, 05:52 PM	#6
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Photos On the Road No it doesn't have any aperture ring The body is not detecting the "A" contact on the mount. In order for your lens to be detected correctly, there needs to be electrical continuity between the center of the "A" contact and the mount face. This can be tested with an ohmmeter if you have one. For a contact map see: Features and Operation of the Ka Mount. The "A" contact is labeled "*" in the diagram. Are you able to check functionality with a different lens? Steve

04-25-2014, 12:20 AM	#7
Photos On the Road Junior Member Join Date: May 2012 Posts: 34 Original Poster	Thank you, this is useful. All other lenses are perfectly functional. I had the same issue years ago with a sigma 70-300 that was damaged by hitting the ground. I have also located the A contact. I have a ohmmeter but i am not sure how to use it in this case

04-25-2014, 01:25 PM	#8
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Photos On the Road Thank you, this is useful. All other lenses are perfectly functional. I had the same issue years ago with a sigma 70-300 that was damaged by hitting the ground. I have also located the A contact. I have a ohmmeter but i am not sure how to use it in this case Well, there you go. The problem is probably with the lens. Test for continuity (0 resistance) across the center of the lens A contact to the face of the lens mount. If the circuit is not open, the lens will not be recognized as supporting automated aperture control by the body. Steve

04-25-2014, 01:44 PM	#9
Photos On the Road Junior Member Join Date: May 2012 Posts: 34 Original Poster	Originally posted by stevebrot Well, there you go. The problem is probably with the lens. Test for continuity (0 resistance) across the center of the lens A contact to the face of the lens mount. If the circuit is not open, the lens will not be recognized as supporting automated aperture control by the body. Steve Thanks a lot. And provided, is it the lens do you think the only solution is to throw it away and buy a new one or is there a way to fix it? Thank you again.

04-25-2014, 03:38 PM	#10
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Photos On the Road Thanks a lot. And provided, is it the lens do you think the only solution is to throw it away and buy a new one or is there a way to fix it? Thank you again. It may be something as simple as a loose wire or a broken solder joint. I can't say what the cost or effort to fix might be. Steve

04-26-2014, 04:49 AM	#11
Photos On the Road Junior Member Join Date: May 2012 Posts: 34 Original Poster	Originally posted by stevebrot It may be something as simple as a loose wire or a broken solder joint. I can't say what the cost or effort to fix might be. Steve Thank you very much for your help. Giuseppe