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06-05-2014, 12:57 AM   #16
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I have the same Sigma 17-50 HSM lens, and at 17mm f2.8 iso 640 from about 2ft away from my monitor I can clearly see moire in the K-30 VF just about every time I focus, just like your no. 13 shot; i.e. your sharpest one. If it helps, this is one of the lenses I gave up trying to adjust using AF charts, I got better results setting up the K-30 AF micro adjustment at infinity and 50mm FL but I think it's a K-30 'characteristic' rather than the lenses as such, in fact I wonder if Pentax cameras have loads of tweaks for their own lenses that just aren't there for 3rd party lenses so we have to play around a bit more to get good results.


Last edited by SteveB; 06-05-2014 at 01:03 AM.
06-05-2014, 12:50 PM   #17
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I use the AF button for focusing as well, but for different reason. At one point I wanted to try it - I didn't like it at first, but now I do, though the placement of the button could be better. But that's a different topic

The zoom trick never worked for me. I noticed early on, after buying the first dSLR (K-x), that focus changes as lens is being zoomed. I tried again just now, this time with little zoom from 20 to 17 and the focus is thrown a lot off. I took pics at both 20 and 17 mm, and it was on the spot @ 20mm.
06-12-2014, 07:52 PM   #18
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In an effort to isolate the problem, try using live view focusing and repeat your tests. Frankly, limiting your test to the monitor screen isn't as reliable as shooting real-world, three dimensional scenes.

I suspect that there might be some validity to the concern about 3rd party lenses and PDAF accuracy. It seems that there are far more complaints about how the faster Sigma lenses often fail to focus consistently than you hear about the Pentax lenses. It also seems like screw-drive lenses tend to be easier to adjust properly. (Then again, fewer fast AF lenses are screw drive.)
06-12-2014, 10:17 PM   #19
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I sent the camera for repairs yesterday. The shots were just to show how much off it can be off and what's really frustrating is that the AF is highly unpredictable. It can be hard to identify a problem using real world scenarios but I photograph at many events and here, I take many group photos and the focus accuracy has become very bad over time, even at lower apertures which at one point I started using.

I have no doubt something is wrong and I do not think it is lens related. What worries me is whether the repair guys will be able to reproduce the misbehavior in order to recognize there indeed is a problem, because of it's randomness. But random in a really bizarre way.

06-13-2014, 09:48 AM   #20
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Absolutely, you did the right thing to send it in. No doubt there is something wrong, and the brand of lens shouldn't make a difference. Unfortunately, though, it is entirely possible that the problem will be less evident with testing done on a Pentax lens. I hope you have a better service center experience this time around.
06-13-2014, 11:17 AM   #21
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QuoteOriginally posted by Zafar Iqbal Quote
What worries me is whether the repair guys will be able to reproduce the misbehavior in order to recognize there indeed is a problem, because of it's randomness. But random in a really bizarre way.
I'm thinking they will clean, adjust and set everything to factory specs. Which should fix the issue. I do not think they will actually have to duplicate the problem. Who knows, it might be a loose adjustment screw that allows a little 'slop' in the focusing. It might be a bit of dust or lint that gets in the way of the focus and occasionally throws it off. Just speculating, but I would not worry about them reproducing anything. My experience has been that the camera came back 'hand tuned' and better than from the factory. YMMV, of course.
06-13-2014, 01:54 PM   #22
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QuoteOriginally posted by jatrax Quote
I'm thinking they will clean, adjust and set everything to factory specs. Which should fix the issue. I do not think they will actually have to duplicate the problem. Who knows, it might be a loose adjustment screw that allows a little 'slop' in the focusing. It might be a bit of dust or lint that gets in the way of the focus and occasionally throws it off. Just speculating, but I would not worry about them reproducing anything. My experience has been that the camera came back 'hand tuned' and better than from the factory. YMMV, of course.
My experience is the opposite and that's why I'm worried Last year I sent in a virtually new K-5 which wasn't autofocusing properly under artificial light. When I got it back it was as if they shiftet the whole spectrum calibration (I have no indepth idea about how phase detection works, so don't take that too literally) and when I got it back, it would focus properly under artifical light, but now be off under natural light - that's a huge bummer. It dragged on for some 6 months with no camera and they weren't able to fix the problem. The good news is, it's not the same company who will be looking at the K-30, but instead someone, supposedly, also more competent.

The warranty for both cameras is running out within the next couple of months - I think I'll be looking extra carefully at my other body to see, whether it should be sent in as well.
06-13-2014, 07:04 PM   #23
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QuoteOriginally posted by Zafar Iqbal Quote
My experience is the opposite and that's why I'm worried
I hope it works out for you, it is a real pain to be without a camera for any length of time. I've had good luck with the repair shop here in the states hope you fair as well this time.

06-14-2014, 06:49 AM   #24
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QuoteOriginally posted by jatrax Quote
I hope it works out for you, it is a real pain to be without a camera for any length of time. I've had good luck with the repair shop here in the states hope you fair as well this time.
Thanks.
07-01-2014, 04:42 AM   #25
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Just got a mail saying I can come by and pick up my camera - I'm too excited. I think I've missed it even though I never was without any camera
07-01-2014, 05:55 AM   #26
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QuoteOriginally posted by Zafar Iqbal Quote
Just got a mail saying I can come by and pick up my camera - I'm too excited. I think I've missed it even though I never was without any camera
Please let us know your assessment of whether it's truly fixed or not.
07-01-2014, 07:21 AM   #27
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QuoteOriginally posted by Zafar Iqbal Quote
Just got a mail saying I can come by and pick up my camera
Yes, do post a report very interested to see if it is fixed and any comments the repair shop made.
07-03-2014, 10:48 AM   #28
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I picked the camera up today and I must say, I'm furious. The comment from them says they upgraded the firmware. That's it. Did it help? Nope!

See for your self's:

Center crops: 2014.07.03a - zafariqbal
Uncropped: 2014.07.03b - zafariqbal

The galleries include all but a two shots taken since I got the camera back. The two excluded shots were accidentally shot @ f6.3 (though one of them still looks slightly out of focus).

Center point used - no recompositioning or anything like that. I was careful and extra slow when focusing and taking the shots, and I re-re-focused plenty of times.

I'll mention again that the lens used (Sigma 17-50mm f2.8) is fine. In fact I used it a lot recently with my other K-30 body and shot during an entire evening and under different lighting (varying natural, few different kinds of artificial and candle), and not once did my mind wander towards the idea, that some shots were off focus because of the camera or lens.

I tried to make it clear to them, that the problem can be illusive, hoping it would make them diagnose it better. I can't express enough how disappointed I am. Now I have to send it back in again, be without my backup body for another couple of weeks.. and MAYBE they will fix it this time.
07-17-2014, 04:08 AM   #29
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My shop forwarded a mail from the repair facility to me, so I could reply and explain things to them directly and hopefully better.

They claim they can't find any problem - they are also wondering I might have missed the fact, that AF is performed by the AE-L/AF button. This last part along with the earlier firmware update makes me question and doubt their seriousness and commitment.

I don't think I mentioned this here, but since this particular body was sent for repairs, I've shot some thousand pics using my other K-30 body, and the lens that is predominantly used on the "bad body". I've yet to see similar issues.

;(
07-29-2014, 03:12 PM   #30
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I got a new mail today, saying they still can't find the problem. They are pointing toward FF issue and asking for a lens so they can verify it.

My question: Is it possible to have a FF issue (with a lens) that behave in such a way, that the focus lands on spot some times, and at random distances other times? I personally do not believe so. Am I mistaken and could there be something about this?

Ps. just this week I shot 2000 pics with the lens that is used the most with the camera body in question, but with my first camera body - no problem what so ever.
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