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01-07-2013, 06:07 AM   #1
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AF Adjustment on K-30

Hey folks,

I'm a noob here

Is it normal that I had to use AF Adjustment on my K-30 to make sure that my Tamron 28-75, and Sigma 70-300 is correctly focusing? I had to set -8 to my Tamron, and -4 to my Sigma lens to have optimal focus (using keyboard, guitarstrings, and focus test charts)

And the second question is what we can consider as sharp image? I'll upload few images that I want to think as sharp image, but I'm not sure (being a noob)

Cheers



Szabolcs

01-07-2013, 01:24 PM   #2
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QuoteOriginally posted by szmatefy Quote
Hey folks,

I'm a noob here

Is it normal that I had to use AF Adjustment on my K-30 to make sure that my Tamron 28-75, and Sigma 70-300 is correctly focusing? I had to set -8 to my Tamron, and -4 to my Sigma lens to have optimal focus (using keyboard, guitarstrings, and focus test charts)

And the second question is what we can consider as sharp image? I'll upload few images that I want to think as sharp image, but I'm not sure (being a noob)

Cheers



Szabolcs
Generally, yes, it's normal unless you need to apply +10 or -10, which might suggest that the lens and camera need professional calibration.

Sharp means that the result of AF is the same as the result of perfect manual focusing, which is achieved when your lens is focused on the same distance as your subject.

Adam
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01-13-2013, 03:46 AM   #3
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Thanks Adam,

My Tamron was set to -8, and Sigma seems to need different settings on different focal length. I asked a friend of mine to bring his superior lens to test, and I do hope that the lens is faulty (it was dirt cheap) and not the camera. It seems that with the Sigma, Live View produces slightly sharper image, and I cannot adjust the AF to achieve the same with the phase detection...
01-16-2013, 02:57 AM   #4
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Fuuny, after few days, I had to readjust, and set to 0 all adjustment. Intersting. Maybe, the AF is not the top when low light condition is present...

04-19-2013, 08:33 AM   #5
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Since then i've readjusted the AF. TAMMY is on -7, Sigma is on -10...should I take my camera to the service?
04-19-2013, 09:57 AM   #6
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It's hard to say unless you do a controlled test using a procedure/test chart like this one: Fixing Front and Back Focus - Introduction - PentaxForums.com

Photos can be blurry for other reasons than just the AF, so I'd definitely double-check before sending your camera in

LensAlign LensAlign MkII Focus Calibration System LA-LA2 B&H

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04-21-2013, 10:23 PM   #7
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I did. The test chart indicated a -10 on my Tammy, however in real life a -7 produces the best result. I wish there would be lense and camera database where you could check your redult against others on the same chart. Is it normal?
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