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09-24-2013, 11:18 AM   #1
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Disappointing K-5 AF accuracy.

My K-5 AF accuracy is really poor... 40%of pics are not focused well. Of course I sent it to PENTAX to fix...

idk about K-5ii2 and K-3, but are those have better AF accuracy??

09-24-2013, 11:28 AM - 1 Like   #2
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Mine seems pretty good - of course there are limits - but under the conditions I'd expect AF to deliver well, it does. I haven't done any lens adjustments either. Hopefully the shop will adjust your unit and you'll be happy.

I don't think the K-3 exists yet, so of course it's better.
09-24-2013, 11:28 AM   #3
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With my K-5 it isn't so much the accuracy of AF but slightly mis-aligned AF points in the veiwfinder, which others have also reported. My center point is at the lower-right corner of the square in the viewfinder. You might check around the edges when the camera comes back.

I'm not sure if II owners see the same thing though.
09-24-2013, 11:48 AM   #4
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Sorry to hear that. I can have problems using PDAF in dimly lit rooms, but that's about it. Oh, and in red-only light, but that shouldn't surprise anyone...

Very thin DoF can also be tricky, but that has less to do with misfocusing, really.

(Talking above about search lights with red filters, not a visit to Amsterdam!)

09-24-2013, 11:58 AM   #5
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A) What version of firmware are you using?
B) Can you post some examples, where you thought the AF should have been better than it was.
C) I'm assuming the camera is still with Pentax, but it will be interested to hear what they say.
09-24-2013, 12:11 PM   #6
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MSL is on the right track. You can't just say "herp my camera sucks" - maybe its you who is doing something wrong.
Sure, maybe it is the camera, but let me assure you that nobody would use cameras that misfocus 40% of the time. But the K-5 is actually very popular and a lot of people get perfectly-focused photos with it. If you have a specific problem, feel free to start a thread, explain what you are doing, what you expect, and what you think is wrong. Then members can help you, or advise you to send the camera for repair (or tell you that it is unfixable, so you can move to another brand). We have had threads where people whined about AF, and then it turned out it was motion blur due to long shutter time, or the DoF was too narrow due to wide aperture..
But since you asked, yes, the AF module is improved on the K-5II - it focuses in dimmer light. And pretty much all AF tests have shown that the K-5II is as good as a Nikon in the same tier. In fact, it often doesn't need the AF assist light when the other brands already do.

Edit: And yes, of course there is chance that you got a bad or damaged camera, that the camera behaves in a way that is incompatible with you or your needs (even though its fine for most people), etc. But you should still be a little clearer when you make a thread.
09-24-2013, 12:12 PM   #7
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Mine is dead on with either Manual focus or AF lenses... I have the k-5 and I use it for every event shots.
09-24-2013, 01:11 PM   #8
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QuoteOriginally posted by MSL Quote
A) What version of firmware are you using?
B) Can you post some examples, where you thought the AF should have been better than it was.
C) I'm assuming the camera is still with Pentax, but it will be interested to hear what they say.
A) recent one
B) I upload it.


Mine is not damaged or have any wrong thing. K-5's AF focus is just suck. Several month ago, the only Pentax photographer changed his camera to D800 because of the focus accuracy.

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09-24-2013, 01:33 PM   #9
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In that photo the dark cloth with the pattern is perfectly in focus. That is also the centre of the photo, where the AF point would be. It also has more contrast than the child's face, which is another reason why the AF would go there. At f2.8 the DoF is just so shallow that even a small miss will be noticeable.
In dark conditions, it is best to use flash and f5.6, 1/125. Or manual focus. The photo is ISO 2000, obviously it was very dark there. And the focus is still good, just not where you imagined it would be, because the camera does not recognize faces, it only looks for high contrast.
09-24-2013, 01:55 PM   #10
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Yep, the pattern is in perfect focus but the depth of field is short due to F2.8 so it doesn't cover the whole face and the face seems to be suffering from motionblur. I can't see the fault in the AF as it grabbed the most defined thing in the AF area and focused perfectly.
09-24-2013, 02:09 PM   #11
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QuoteOriginally posted by Na Horuk Quote
In that photo the dark cloth with the pattern is perfectly in focus. That is also the centre of the photo, where the AF point would be.
Exactly.

OP: I assume you would rather have had, or were expecting the child's right eye, if not the whole face, in focus, but the camera had no way of knowing that. The EXIF shows the focus range as "macro", and the aperture as f2.8. As Na Horuk pointed out, f2.8 has very shallow DOF. In this case it is particularly shallow due to the close working distance.
09-24-2013, 02:19 PM   #12
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Please post more examples.

Cameras are tools - not knowing how to properly use a tool does not mean the tool is defective.

That being said, there are many users who have found the k-5 to not be as accurate as they would like, and some of those users are finding that the k-5II is more decisive and accurate.

My k-x is much worse at low-light focusing than a k-5, and I still manage to make it work. A lot of it is about familiarity, knowledge of little tricks to "help" the AF, and knowing the actual limits of the camera.
09-24-2013, 02:36 PM   #13
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Looks like there could also be motion blur contributing to the problem. 1/80 is really not fast enough for kids, certainly not mine.

But I have to agree with the others, the problem is primarily the choice of focus target. Select a better focus point, or use focus-and-recompose technique (hard with moving kids). And bump your ISO, use flash, etc.

There could be a back/front focus problem in addition to the problem of the focus target, but it would not cause this much misfocus. You can encounter this kind of discrepancy in a telephoto lens at longer distances, but for this to be the reason for the problem at 31 mm focal length, it would have to be so bad that none of your shots will be in focus, not just 40%.
09-24-2013, 03:29 PM   #14
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A small, but significant point- have you calibrated and adjusted the af for your body/lens combination? I thought I had done a good job using the ruler markings method for my lenses, but then iI bought a 'lenscal' a couple of weeks ago and used that to calibrate.... wow what a difference. Every manufactured item has a level of tolerance, it may just be that your camera AF unit and lenses need to be adjusted to play nicely together

I highly recomend to anyone to spend a while with this device and their camera/lens combinations.

Datacolor SpyderLENSCAL - The Smarter Camera Focus Calibration Tool - Datacolor Imaging Solutions
09-24-2013, 05:37 PM   #15
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QuoteOriginally posted by rlatjsrud Quote
Mine is not damaged or have any wrong thing. K-5's AF focus is just suck. Several month ago, the only Pentax photographer changed his camera to D800 because of the focus accuracy.
The K5 does have focus issues, but I'm not convinced yet you have an exceptional problem. Right now you are pushing the limits of wide open aperture and slow shutter speed.

If I'm shooting my kids under better lighting, but where it is still limited, I'll also get a lot of fuzziness because kids don't sit still. You need to be above 1/200 or so to avoid most motion, and even then, it is easy for hands to be flapping about.

Post a few more, especially under easier lighting conditions and lets see what we can figure out about your camera and the way it is being used.
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