K20D won't go into AF on Sigma lens

Pauld · 06-22-2012, 09:27 AM

I have a good one for everyone to figure out. Last week I mouned my Sigma 18-50 onto my camera and it wouldn't go into AF mode. When I went into Liveview (which I never use) the image was jumpinig all over the place. I tried every switch combination known to man and nothing. Today I mounted my Sigma 50mm F1.4 and the exact same thing occured. I tried other Sigma lens and they work fine. I mounted both lenses onto my back-up K10D and they work fine and yes, I already reset my K20 back to factory settings and they both are still in MF only. I have no idea what the problem is but it's a little frustrating to say the least

What's up with that?

Vasyl · 06-22-2012, 09:38 AM

have you tried the other AF lenses on the K20D, let's say Pentax 18-55mmm?
Did it work?

Pauld · 06-22-2012, 10:07 AM

Sure have and they work just fine.

eddie1960 · 06-22-2012, 10:11 AM

and have you tried cleaning the contacts on the lens and the body with an eraser?

Philoslothical · 06-22-2012, 10:26 AM

Yep, this kind of issue is almost always a result of dirty contacts. I'd go with a clean, dry cloth, first.

Pauld · 06-22-2012, 11:03 AM

Didn't do a thing. Lenses work fine on the K10 but not so much on the K20.

Pauld · 06-23-2012, 01:03 PM

Anyone have any ideas??

06-22-2012, 09:27 AM	#1
Pauld Veteran Member Join Date: Nov 2009 Location: Calgary, Alberta Photos: Gallery \| Albums Posts: 507	K20D won't go into AF on Sigma lens I have a good one for everyone to figure out. Last week I mouned my Sigma 18-50 onto my camera and it wouldn't go into AF mode. When I went into Liveview (which I never use) the image was jumpinig all over the place. I tried every switch combination known to man and nothing. Today I mounted my Sigma 50mm F1.4 and the exact same thing occured. I tried other Sigma lens and they work fine. I mounted both lenses onto my back-up K10D and they work fine and yes, I already reset my K20 back to factory settings and they both are still in MF only. I have no idea what the problem is but it's a little frustrating to say the least What's up with that?

06-22-2012, 11:03 AM	#6
Pauld Veteran Member Join Date: Nov 2009 Location: Calgary, Alberta Photos: Gallery \| Albums Posts: 507 Original Poster	Didn't do a thing. Lenses work fine on the K10 but not so much on the K20. Last edited by Pauld; 06-22-2012 at 02:41 PM.

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06-22-2012, 09:38 AM	#2
Vasyl Veteran Member Join Date: Aug 2010 Photos: Gallery Posts: 648	have you tried the other AF lenses on the K20D, let's say Pentax 18-55mmm? Did it work?

06-22-2012, 10:07 AM	#3
Pauld Veteran Member Join Date: Nov 2009 Location: Calgary, Alberta Photos: Gallery \| Albums Posts: 507 Original Poster	Sure have and they work just fine.

06-22-2012, 10:11 AM	#4
eddie1960 Veteran Member Join Date: Aug 2010 Location: Toronto Photos: Gallery \| Albums Posts: 13,666	and have you tried cleaning the contacts on the lens and the body with an eraser?

06-22-2012, 10:26 AM	#5
Philoslothical Veteran Member Join Date: May 2011 Posts: 1,889	Yep, this kind of issue is almost always a result of dirty contacts. I'd go with a clean, dry cloth, first.

06-23-2012, 01:03 PM	#7
Pauld Veteran Member Join Date: Nov 2009 Location: Calgary, Alberta Photos: Gallery \| Albums Posts: 507 Original Poster	Anyone have any ideas??