focus problems

My K10d is a little hit and miss regarding autofocus. I realise that in low light or low contrast situations this will be the case.

Would a dusty reflex mirror or dirty focus screen affect autofocus performance?

My centre point indicator is not perfectly central in the screen. Is this crucial?

Could the lens be faulty?

Any comments would be much appreciated

Hi Kiwao,

If the hit and miss experience happens to you with a number of your lenses, then it is unlikely to be all of those lenses.

The K10d has never been a star performer with its autofocus (I have had one for nearly 4 years, so I'm speaking from personal experience).

I tend to use mine in manual focus mode - it's no big deal, just a habit you get back into.

As to the centre point indicator, you might think about putting the camera in for a clean and service? That way you can be confident about resolving those issues you've raised here.

Properly exposed shots with the K10 are as good as anything else for most things - it's still a good camera.

I think the problem was always with the earlier build K10Ds, the ones built at the same time the GP Edition was launched were apparently much better.

There is an old thread on PentaxForums about the correlation between serial number and AF issues and the earlier ones presented with more problems apparently.

Thanks for the replies. The focusing problem seemed to become worse when I started using my newly acquired 77 ltd so thats why I asked if a lens could have a fault that could cause this.

After googling I found that the autofocus mechanism was under the reflex mirror and so I thought if this is dusty then cleaning it could improve the situation so I took a brillo pad, only kidding, micro fibre cloth and gently cleaned it. I have since read that this was a bad move and I have probably damaged the surface of the mirror which has probably made the autofocus accuracy worse??

Hmm - that might be an additional reason to send it in for inspection, clean and service...