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07-14-2011, 07:55 PM   #1
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Upgrade K-r to K-5 to alleviate front focus woes?

So I've been debating lately if I should upgrade my K-r to a K-5. One of my problems with the K-r has been front focusing. I've read a bunch about K-5 front focus issues, but it seems to happen only in tungsten light with about 3 EV and darker.

So I was wondering if my K-r would front focus in a similar way. Quick background: I already sent the camera in for repair for front focus issue. It came back with the issue still present.

I tested these 3 lenses:
Tamron 70-300mm F/4-5.6
Sigma 24mm F/1.8
Sigma 30mm F/1.4

All tests were on a tripod with auto white balance unless otherwise noted.

First I tested the Tamron at 300mm F/5.6. This is a 1:2 macro at minimum focusing distance. To my surprise, even down to 1 EV of tungsten, this lens was not front focusing.

Then I tested the Sigma 24mm at F/2.0. This lens had a slight, but consistent front focus from 8EV down to 1 EV.

Finally I tested the Sigma 30mm at F/1.4. Even at 8EV of tungsten light, this lens very noticably front focused. Switching to 8EV of soft white fluoresent light made the lens focus correctly. Then I tried the tungsten light again, but with white balance set to incandescent. This helped the focussing a lot. And when I dialed in a -10 for fine focus adjust, it was close to spot on.

My conclusions for the K-r are:
Front focus is heavily lens dependent.
front focus, when present, happens in tungsten light.
setting the white balance to the incandescent preset helps
Front focus happens even in brighter situations.

So if I were to upgrade to a K-5, could I enter lens profiles for all these lenses to completely fix my problem? And do I not even have to worry about correcting them at 4EV and above? Has anyone else upgraded to the K-5 from the K-r and had their focusing problems fixed? I know may people still have FF issues with the K-5, but I'm looking for a relative judegement on how bad the issue is between the cameras. Thanks for any input!


Last edited by devorama; 07-15-2011 at 12:40 PM.
07-14-2011, 11:19 PM   #2
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Just remember to re-set your K-r to factory defaults before you pass it onto anyone, if you do decide to sell it. Your adjustments are pretty wild.

Also all FF/BF conclusions are heavily dependent on lens/body build tolerances and how the two interact, not to mention the rigour of your testing methodology. Because of all these variables, if you go looking for issues, you will probably find them no matter what camera body you move to.
07-15-2011, 01:57 AM   #3
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I upgraded from the K-r to the K-5, I got some fairly inconsistent results with the K-r and feel that the K-5 isn't much better but there is more leeway to tweak the AF adjustment settings. I get great results with the DA*50-135 (better at 135) but feel that my DA40 is off but can't seem to find the sweet spot in the AF adjustments. I'll send the cam & lenses in for calibration if I can't work it out. Apart from that issue, the K-5 has been amazing.
07-15-2011, 07:14 AM   #4
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If you are upgrading just because of focus woes, I would advise to try out a k-5 somehow (rent it or buy it new from a place where you can return within 15 days). Focus is still a bit dodgy in certain k-5 units, so it is best to try to your satisfaction first.

10-30-2011, 11:00 PM   #5
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I expect Pentax to pay me the difference if the only solution is to upgrade to K-5.
10-30-2011, 11:40 PM   #6
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Well I finally upgraded to the K-5, but the darn thing still front focuses. Blerg!
10-31-2011, 04:11 AM   #7
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QuoteOriginally posted by devorama Quote
Well I finally upgraded to the K-5, but the darn thing still front focuses. Blerg!


...I was thinking of a small pentax kit that would have included a K5..second guessing that move now ..!
10-31-2011, 05:46 AM   #8
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I finally just threw up my hands with the K-5 Under the canopy with fast glass it was just useless. But in good light you could not ask for a better camera. With two copy's and both sent back and both come back the same. I have a hard time believing there are better ones out there. Good advice to rent or buy with a grace period. So you can evaluate your self if it is going to be a problem with your style of shooting. If not it is a wonderful camera in every other way.

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