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09-02-2011, 03:08 PM - 1 Like   #1
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K-5 AF (back focus) Issue...

Using my 3-month-old K5 with DA*200 & DA* 50-135 zoom, I'm noticing that I'm missing too many good shots because of softness. This seems to be true whether shooting a bug on a weed stem or portaiture. I shot about a dozen images of my wife yesterday evening in beautiful, low-angle, warm sunlight, and none were useable even though the AF was set at "center". When opened on my computer screen, all were back-focused by a few inches.

Today I set up a test shot using 5 table knives laid about 2" apart on a white countertop and perpendicular to the camera with the camera about 6-feet away. I focused on the middle knife with AF set on "center". I started with the 200mm lens, camera on tripod, and took individual images, enlarging each to carefully examine results on the display. With the middle knife in focus, the two knives behind were clearly sharper than the two in front. I used 2.8 aperature to force depth-of-field.

I used the fine tuning menu to move the focal point closer by 2-step increments (favoring front) and continued to test each setting. Not until I reached "+8" was I able to get about equal softness on the first knife and the last in line with the focal point still on the one in the middle.

I then switched lenses to the 50-135 zoom and did the same series of visual test shots, blowing up each one in the display to view them in detail. "+8" worked as well with this lens as the 200mm.

Switching to the Sigma 17-70 zoom, I repeated the above with the same results. "+8" works on this lens also.

I also used the "selective" focus setting in addition to the "center" setting for all of the above and found that this setting seemed to move the focal point 1-knife closer when the red pipper was set for the center knife. When the pipper was moved to the bottom (closest) focal choice (the first knife in the lineup of 5) it was more in-focus, but still definitely still softer than the next in line. I'm leaving the setting of "+8" "for ALL lenses" and will shoot some more images this evening to double check these settings in real shooting situations.

My question: Is it typical of the K-5 to need this much "fine tuning" to get the results the camera is supposed to be capable of? Does this signify a need for warranty service? Are others experiencing a similar problem with K-5 auto-focus?

And by the way, the lens button fell off, also.

grollands38


Last edited by grollands38; 09-02-2011 at 03:33 PM. Reason: additions/corrects/better grammar
09-02-2011, 03:16 PM   #2
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Well when this works then I think all is fine.
09-02-2011, 03:44 PM   #3
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If it is correctable by the microadjustment, then there is no need to worry. That's precisely why the microadjustment is there. I had similar problem with K10D. I had to go to service as it didn't support microadjustment. It was all out of warranty, but the adjustment (here in Prague) was only equivalent of 20$ per lens adjusted. The service employee told me that small inaccuracy may develop over time and it is a good practice to check the equipment every few years. But almost no one does that - instead we buy new cameras...
10-31-2011, 12:50 PM   #4
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As an update: I, too, lost the lens release button on my K-5 and was directed by Pentax to send the camera to Chandler, AZ. I alluded to the back-focus issue among my concerns. The reply from CRIS Camer Repair listed a "fix" for that problem in addition to their replacing the button, plus, "examining and cleaning to factory specs". Since then, I could not be more pleased with the AF function. I also downloaded the focus check page and accompanying instructions on how to set up and use it to check any lens/camera combination. This, too, has been a big help. Thank you. The K-5 is a great camera and the prime Pentax DA* lenses (DA* 200/DA* 50-135) reviewed on Pentax Forum make the system complete. Pentax Forum has become an important partner in my enjoyment of my photography semi-pro/hobby.

10-31-2011, 04:46 PM   #5
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QuoteOriginally posted by grollands38 Quote
As an update: I, too, lost the lens release button on my K-5
That issue alone almost decided me against the K-5. I mean it was just one problem too many with the thing.
But I took the plunge anyway and bought an ostensibly new one yesterday. It was manufactured back in March. I hope that wasn't one of the worse "vintages" for the camera. Seems ok but I haven't had any time to really check.

First thing I did: I put gaffer tape over the lens release button.
Good luck with yours!
10-31-2011, 06:53 PM   #6
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QuoteOriginally posted by pentup Quote
That issue alone almost decided me against the K-5. I mean it was just one problem too many with the thing.
But I took the plunge anyway and bought an ostensibly new one yesterday. It was manufactured back in March. I hope that wasn't one of the worse "vintages" for the camera. Seems ok but I haven't had any time to really check.

First thing I did: I put gaffer tape over the lens release button.
Good luck with yours!
Deleted due to not being helpful at all.

Last edited by Ex Finn.; 11-01-2011 at 09:18 AM.
10-31-2011, 07:04 PM   #7
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QuoteOriginally posted by Ex Finn. Quote
Oh come on, doom and gloom. It either works or it does not. Period.
Please, get over it. It's a piece of tape, for crying out loud, why does it offend you? It might prevent a hassle for me that others have experienced. The fanboy nonsense is never helpful. "It either works or it does not" is meaningless. "Doom and gloom" my eye.
10-31-2011, 07:16 PM   #8
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Deleted, same reason as my last post.


Last edited by Ex Finn.; 11-01-2011 at 09:19 AM.
10-31-2011, 07:32 PM   #9
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The lens release button business has popped up (or should I say popped off?) in a number of threads; in one of them, someone said he'd had to send the camera in for servicing with the lens still attached, because he couldn't get the lens off without the button. That sounded like it would be quite an inconvenience; one might have a backup for the camera, but not a good substitute for the lens, and servicing times lately can be very long. But it seemed strange to me that one couldn't release the lens without the button somehow, so I asked in another thread, and got this reply:

QuoteOriginally posted by rtpguy Quote
You should be able to use a pen or something similar to depress the internal mechanism - there isn't much to the lens release button, it's just a piece of plastic with a circlip stopping it from coming out of the body, until/if the circlip breaks or pops off..
In any event, I bought the thing fully aware of the QC issues; they didn't outweigh the desirability of the camera.

I went through focus adjustment headaches with the K-7 that really weren't worth the time; relying on quick shift and trusting my eyes when it's available is how I plan to deal with AF issues with the K-5, whenever possible.
10-31-2011, 07:38 PM   #10
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QuoteOriginally posted by Ex Finn. Quote
As far as it working or not , that is non negotiable, no matter what it is.
Um, yeah. The light is on, or it's off. The bill is paid, or it's not. The girl is pregnant, or she's not. I get it. I didn't say it was untrue. I said it was meaningless.
10-31-2011, 07:59 PM   #11
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Deleted, see my last 2 posts. Hey, it`s Halloween.

Last edited by Ex Finn.; 11-01-2011 at 09:21 AM.
10-31-2011, 08:08 PM   #12
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QuoteOriginally posted by Ex Finn. Quote
That pretty much sums it up. Found anything else wrong lately ?. Just asking
I still have no idea what the hell you're talking about. I haven't stated anything here that I've "found wrong."
11-01-2011, 01:25 AM   #13
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My 2c worth re your AF adjustment issues:

- buy something like a DataColor SpyderLenscal to ensure you are doing AF adjust consistently and accurately. It's too easy to do it wrong. It's only $50 or so;

- I hope you aren't using any UV filter or other filters on those lenses that are behaving erratically... Poor quality UV filters can create AF problems.
11-01-2011, 07:56 AM - 1 Like   #14
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Removing the lens when the release button is gone...

'Sounds tacky, but it works. Use a medium-sized paper clip and open out the short "leg". Insert it into the small hole that's visible where the release button pin used to reside and push it in gently. While holding it in, apply a slight twist to the lens and it's off. You can attach or remove lenses using this make-shift method. As I said, it's tacky to be doing this to a camera that has the name Pentax on it, but you gotta be inventive.

I still love the camera!
11-01-2011, 03:08 PM   #15
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QuoteOriginally posted by grollands38 Quote
'Sounds tacky, but it works. Use a medium-sized paper clip and open out the short "leg". Insert it into the small hole that's visible where the release button pin used to reside and push it in gently. While holding it in, apply a slight twist to the lens and it's off. You can attach or remove lenses using this make-shift method. As I said, it's tacky to be doing this to a camera that has the name Pentax on it, but you gotta be inventive. I still love the camera!
Excellent!
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