K30 focus inaccuracy


piotro

Link Posted 18/11/2012 - 12:50
So, came back from holiday, looking at pictures taken with K30 bought recently and plenty of them are not in focus with clear front focusing. But some have focus correct (significantly less then 50% overall).
I did run a quick test just before travel and applied front focus correction to particular lens I was taking with me (tamron 18-250), but it didn't help at the end as I've found.

So I run a bit of tests today, trying couple of lenses and:
- tamron 18-250mm - strong front focus, but focusing seems to be inconsistent, from time to time focusing error is different (same focal length), different focal length may give different focus error as well. Tried also focus with live view and it tend to give strong back focus, but again is not consistent. Both focusing errors are outside camera adjustment range (-10 - +10).
- pentax 60-250mm, some front focus again, focusing bit inconsistent as well, again live view focusing can give completely different result.
- pentax 100mm f2.8 macro, slight front focus, live view focusing gives consistent results.
- tamron 90mm f2.8 macro - as 100mm one.

So I would guess camera need slight correction for front focus - believing in results based on two primes, but this is not going to help with some lenses (individual correction out of range and sometimes results completely different with phase or contract focusing).
Anyone noticed similar issues with K30?
--
http://piotr.zenfolio.com
Last Edited by piotro on 18/11/2012 - 12:56

jblair

Link Posted 18/11/2012 - 15:26
Hmmmm . . . I too am a new K30 owner and have, on occasion, noticed some pictures out of focus. I had assigned blame to the operator (me) and probable rookie errors.

My most used lens is a Pentax 18-250. How did you perform your tests?
jblair

piotro

Link Posted 18/11/2012 - 17:19
You can check focus accuracy using one of many focus charts, one example:
http://pentaxdslrs.blogspot.co.uk/2008/06/part-1-autofocus-adjustment-for-pentax...

Or just using whatever you have around, that will give you a chance to "read" results, look at the chart and you will get the idea.
--
http://piotr.zenfolio.com

jblair

Link Posted 18/11/2012 - 22:25
Thank you!

I hadn't noticed the issue with my K10d. And, I may not have an issue, just becoming a bit more aware of details.
jblair
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