K10D's autofocus has gone wonky

E-man · 12-11-2017, 10:23 PM

So I shot a few frames with my K10D today and noticed the autofocus was having difficulty focusing. A half-push on the shutter button makes the focus go all the way out, then the next half-push makes it go all the way in. Does it both in AF-S and AF-C. Manual focus works just fine. I tried three different lenses with the same result. The camera only has 5,700 shutter actuations. Any ideas? Thanks in advance.

Adam · 12-11-2017, 10:46 PM

Could be debris in the mirror box. That's the first thing I would check.

Fogel70 · 12-12-2017, 02:30 AM

Is the viewfinder dark too? If that is the case it maybe a problem with the aperture mechanism in the camera.

I once had a problem with a spring for the lever in the camera that holds the aperture fully open on the lens.
The spring had jumped off the lever and it was easy to hook it back on. Without the spring the lens will always be fully stopped down (when aperture is controlled by camera), which makes it too dark for AF-sensor to lock focus. If you have a AF lens with aperture ring you can test if you notice any difference if you set the aperture manually with the aperture ring.

There is some more info on this problem in this thread.
1st Problem ever on my K10D from new - PentaxForums.com

E-man · 12-12-2017, 08:48 AM

The viewfinder isn't dark. The lens appears to stop down normally. The photos I took yesterday focusing manually were properly exposed.

E-man · 12-18-2017, 01:15 PM

I haven't figured out any real solutions to the focusing problem with this camera but I did notice something odd when I was messing with it a couple of days ago. The little red blip that comes up in the viewfinder to let you know what the camera is focusing on isn't anywhere near the center of the screen. It comes up way the heck over to the right. Weird...

**paulh** · 12-18-2017, 01:40 PM - **1 Like**

Originally posted by E-man

I haven't figured out any real solutions to the focusing problem with this camera but I did notice something odd when I was messing with it a couple of days ago. The little red blip that comes up in the viewfinder to let you know what the camera is focusing on isn't anywhere near the center of the screen. It comes up way the heck over to the right. Weird...

Sounds like your AF point is off. Is your rear 4 way pad ring set to center-point focus (square with a dot in it) ? If it's set to SEL, your focus point can be anywhere you select.

E-man · 12-20-2017, 12:00 PM

Paul, you're freakin' brilliant!!! That solved the problem. It was indeed set to SEL. Now it's on center-point and everything's copacetic again. And to think, I was seriously considering writing that camera off as a loss and putting it up on eBay real cheap to get rid of it. Glad I held off. Thanks, you just made my day. If it weren't such a dreary, rainy day here, I 'd take the camera out and shoot some pictures to celebrate!

Last edited by E-man; 12-20-2017 at 12:07 PM.

**paulh** · 12-20-2017, 02:17 PM

Originally posted by E-man

I was seriously considering writing that camera off as a loss and putting it up on eBay real cheap to get rid of it.

Be sure to let me know if you decide to do this!

Glad things worked out.

12-11-2017, 10:23 PM	#1
E-man Veteran Member Join Date: Aug 2012 Posts: 678	K10D's autofocus has gone wonky So I shot a few frames with my K10D today and noticed the autofocus was having difficulty focusing. A half-push on the shutter button makes the focus go all the way out, then the next half-push makes it go all the way in. Does it both in AF-S and AF-C. Manual focus works just fine. I tried three different lenses with the same result. The camera only has 5,700 shutter actuations. Any ideas? Thanks in advance.

12-11-2017, 10:46 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Could be debris in the mirror box. That's the first thing I would check. 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:

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12-12-2017, 02:30 AM	#3
Fogel70 Pentaxian Join Date: Sep 2009 Location: Stockholm, Sweden Photos: Albums Posts: 3,062	Is the viewfinder dark too? If that is the case it maybe a problem with the aperture mechanism in the camera. I once had a problem with a spring for the lever in the camera that holds the aperture fully open on the lens. The spring had jumped off the lever and it was easy to hook it back on. Without the spring the lens will always be fully stopped down (when aperture is controlled by camera), which makes it too dark for AF-sensor to lock focus. If you have a AF lens with aperture ring you can test if you notice any difference if you set the aperture manually with the aperture ring. There is some more info on this problem in this thread. 1st Problem ever on my K10D from new - PentaxForums.com

12-12-2017, 08:48 AM	#4
E-man Veteran Member Join Date: Aug 2012 Posts: 678 Original Poster	The viewfinder isn't dark. The lens appears to stop down normally. The photos I took yesterday focusing manually were properly exposed.

12-18-2017, 01:15 PM	#5
E-man Veteran Member Join Date: Aug 2012 Posts: 678 Original Poster	I haven't figured out any real solutions to the focusing problem with this camera but I did notice something odd when I was messing with it a couple of days ago. The little red blip that comes up in the viewfinder to let you know what the camera is focusing on isn't anywhere near the center of the screen. It comes up way the heck over to the right. Weird...

12-18-2017, 01:40 PM - 1 Like	#6
paulh Site Supporter Join Date: Sep 2010 Location: DFW Texas/Ventura County, CA Photos: Gallery \| Albums Posts: 33,315	Originally posted by E-man I haven't figured out any real solutions to the focusing problem with this camera but I did notice something odd when I was messing with it a couple of days ago. The little red blip that comes up in the viewfinder to let you know what the camera is focusing on isn't anywhere near the center of the screen. It comes up way the heck over to the right. Weird... Sounds like your AF point is off. Is your rear 4 way pad ring set to center-point focus (square with a dot in it) ? If it's set to SEL, your focus point can be anywhere you select.

12-20-2017, 12:00 PM	#7
E-man Veteran Member Join Date: Aug 2012 Posts: 678 Original Poster	Paul, you're freakin' brilliant!!! That solved the problem. It was indeed set to SEL. Now it's on center-point and everything's copacetic again. And to think, I was seriously considering writing that camera off as a loss and putting it up on eBay real cheap to get rid of it. Glad I held off. Thanks, you just made my day. If it weren't such a dreary, rainy day here, I 'd take the camera out and shoot some pictures to celebrate! Last edited by E-man; 12-20-2017 at 12:07 PM.

12-20-2017, 02:17 PM	#8
paulh Site Supporter Join Date: Sep 2010 Location: DFW Texas/Ventura County, CA Photos: Gallery \| Albums Posts: 33,315	Originally posted by E-man I was seriously considering writing that camera off as a loss and putting it up on eBay real cheap to get rid of it. Be sure to let me know if you decide to do this! Glad things worked out.