Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
04-12-2018, 12:05 PM   #1
Site Supporter
Site Supporter

Join Date: Mar 2013
Location: Montreal
Posts: 492
K10d Backfocusing - In auto and manual focus modes! Physical issue?


Bought a used k10d, and noticed that everything is a bit out of focus - using AF or MF. No such issues with my K-5 using same lenses. (M and F series primes, tried w/ 18-55 and F35-105 and same result). And yes, all ok w/ diopeter adjustment... (which wouldn't affect AF anyway)

Got to a bit of testing, and it seems that my eye and the AF agree - but that the results are not in focus. Backfocusing is clearly found when shooting a brick wall, F50/1.7 wide open at an angle, and straight on the wall is blurry. Using AF or MF.

Any help? Anyone ever pulled one of these apart? Would be happy if all were ok in MF, as I don't use AF much....


04-12-2018, 12:43 PM   #2
Otis Memorial Pentaxian
Loyal Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 33,237
QuoteOriginally posted by gdneil Quote
Bought a used k10d, and noticed that everything is a bit out of focus - using AF or MF
The PDAF system and viewfinder manual focus use a different light path, so most potential causes would not affect both paths. Questions:
  • Are you doing manual focus using the viewfinder focus screen or are you using AF confirm (beep and green hexagon in the viewfinder)?
  • Is there any chance the factory AF settings might have been fiddled with using the so-called debug mode? The former owner might know.
  • How is the general AF performance (speed and ability to lock)?


( years with a K10D before purchase of K-3 in 2014...tons of manual focus work..)
04-13-2018, 12:56 PM   #3
Site Supporter
Site Supporter

Join Date: Mar 2013
Location: Montreal
Posts: 492
Original Poster
Thanks for the reply, and to answer your questions:

-Manual focus with the viewfinder focus screen, noting that the AF confirm usually agrees with my eye
-I forgot about the debug mode - and bought from classifieds locally, and can't contact former owner. But then I can search on debug mode here and figure it out..
-AF seems fine in speed and lock. (and I have it on center point focus, by the way)

I think my approach will be as follows:

1) Work on shims for the focus screen - seeing that people have made them out of various materials, might give it a try?
2) After MF good, and assuming I can get it within acceptable standards, try to mess with debug mode for aufo-focus?

I had forgotten about the shim idea when I posted yesterday.

Does this sound reasonable?

  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
af, bit, camera, focus, k10d, mf, pentax help, photography, troubleshooting, wall
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
AF Backfocusing 23mystiq Pentax SLR Lens Discussion 18 08-03-2015 03:03 PM
Do Pentax 10-17mm, Sigma 10-20, and Tamron 10-24 have a physical aperture control? torontoem4o Pentax SLR Lens Discussion 3 11-29-2013 10:04 AM
Backfocusing for the FA*300 f2.8 on K5 Ltd Mundus Pentax K-5 11 03-08-2013 09:09 AM
Sigma 135mm 1.8 backfocusing problem cyclone3d Troubleshooting and Beginner Help 15 07-02-2011 02:04 PM
Backfocusing 40mm Ltd schmik Pentax SLR Lens Discussion 25 04-04-2009 02:58 PM

All times are GMT -7. The time now is 07:06 AM. | See also:, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]