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07-05-2012, 04:59 AM   #76
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One thing I would like to mention in regard to the K-5 is sample variation. I have run multiple K-5 bodies through controlled tests. (Involving tripods, a "focus align" brand target, and so on) I have found a repeateable variation in the diffrent K-5 bodies' ability to lock AF on target in both good lighting and bad.

The K-5 body I have now I bought used and am very happy with. It's AF is noticeably better than the others I have tried. It suffers much less from the "low light AF" concerns and it also locks AF in good light more consistantly and repeatably. The only down side is that this body's AF "mid-point" is way off, so I had to change the offset in the service menu to allow even +10 to be enough for some of my lenses. But I can deal with that.

07-05-2012, 05:13 AM   #77
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QuoteOriginally posted by audiobomber Quote
I've found the chart at the bottom of this page invaluable in checking for focus error:
http://focustestchart.com/focus21.pdf
Thanks. I used the exact same chart though Page 18.

QuoteOriginally posted by apisto Quote
The only down side is that this body's AF "mid-point" is way off, so I had to change the offset in the service menu to allow even +10 to be enough for some of my lenses. But I can deal with that.
That was my experience as well with the unboxed K-5. I couldn't take too many pics to see how good or bad it was and since i also didn't understand the problem well enough back then, I wasn't willing to accept it.
07-05-2012, 06:45 AM   #78
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I'm not saying it cant do it only that you cant rely on it to actually to focus on it every time.
Let me state it differently, can you tell me with 100% certainty the focus was aiming for the tree and not the wall?
If you cant then you agree that there is the possibility that it did focus on the wall.
07-05-2012, 07:21 AM   #79
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I see where you are getting at. The micro adjustment offsets the focus so much, that it makes is difficult to say if I indeed had targeted the tree or not. Lets me see if I can find something less confusing.

Edit:
I hope this one is better: http://zafariqbal.smugmug.com/Shares/2012/20120705b/23983779_HHvXnP

Used tripod.
First 5 shots are focus consistency test shots.
Last three were shot @ Micro Adjustment @ 0, -10 and +10, respectively.
All shots refocused from MFT.

The focus does not shift by millimeters (it's relative to distance). The distance in these photos is less than the one from original K-5 photos, but the focus shift is still spread across meters. The K-5 was back focusing by so much, that I could not shift it enough as I claimed.


Last edited by Zafar Iqbal; 10-29-2013 at 02:04 PM.
07-05-2012, 08:57 AM   #80
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Again, utter nonsense. Your entire testing methodology remains flawed by the fact that you have not yet learned how large your AF sensors are and the sgnificance of this. Your tests continue to feature focus targets that do not cover the range of the sensor, so you have *no diea* where the camera is trying to focus.
07-05-2012, 09:07 AM   #81
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I wonder where you are getting your "facts" from.

twitch's reply made me curious enough to see exactly where the boundaries are and if ther indeed is a + shape to it. I used paperclips and the outermost boundaries are just at or with within the marked circle on the focusing screen, on this particular K-r I have.

I'd very much like comments, suggestions etc, and even though I not might agree to all of them, I'm still open minded enough to at least give them a try.

You however are just dismissing all of it on the basis of what? Provide some facts instead of just saying it's nonsense. I do not mean to be rude, but you are way off, again.
07-05-2012, 09:23 AM   #82
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QuoteOriginally posted by Zafar Iqbal Quote
I see where you are getting at. The micro adjustment offsets the focus so much, that it makes is difficult to say if I indeed had targeted the tree or not. Lets me see if I can find something less confusing.

Edit:
I hope this one is better: 2012.07.05b - Zafar Iqbal's Photos | SmugMug

Used tripod.
First 5 shots are focus consistency test shots.
Last three were shot @ Micro Adjustment @ 0, -10 and +10, respectively.
All shots refocused from MFT.

The focus does not shift by millimeters (it's relative to distance). The distance in these photos is less than the one from original K-5 photos, but the focus shift is still spread across meters. The K-5 was back focusing by so much, that I could not shift it enough as I claimed.
That's much better, it takes out most of the random things.

The -6 and -10 surely do preform the best, what if you stand a bit closer to the wall?

About the focus shift, we are talking about the focus shift on the sensor side when we are talking about this and then we are measuring things in micrometers.
Those -10 +10 adjustments are 10 micro meter per step, i hope that explains things a bit.
07-05-2012, 09:23 AM   #83
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QuoteOriginally posted by Williunck Quote
Marc, as a moderator it seems like you could be a lot more helpful and a lot less condescending. He asked for advice on how you would run the tests which you still haven't given him in 2 posts now.
Why do think it is my job to explain the flaws inthe test as run, or to offer information how to run a test, when as you have observed, others have already chimed on that topic? And in just a minute of searching, you can find all the info you want on focus testing. The OP was denying the information that was already presented. He didn,t need mew information, he needed convincing to listen to the information he had already been given. Which in my opinion required a more direct tone. And FWIW, just because I am a moderator does not every post I make is in that capacity.

07-05-2012, 09:31 AM   #84
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QuoteOriginally posted by Zafar Iqbal Quote
I wonder where you are getting your "facts" from.
Your posted shots. As I have said, your tests are improving, but you continue to act as if your initial shots have some sort of validity. To state it more plainly - at this point you have zero reason to believe your camera has any problem whatsoever. Not one signle test you have posted constitutes any reason to believe any such thing, and indeed, some of them seem to prove pretty conclusively it does *not*. But you are allowing yourself to be confused by your flawed shots, still thinking that poor focus adjustment was responsible for things going on in the first batches of completely flaws shots. You need to toss out those shots as completely worthless and start over. If you can create a valid test that shows any sort of problem, *then* you can proceed to playing with focus adjustment. Right now, though, your just randomly throwing darts.
07-05-2012, 09:36 AM   #85
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I can understand Zafar's disappointment. My first K-5, the focus was way off, coming from a shoot that my K20d would have handled with no issues, I came home to see a bunch of missed images. I sent that camera back without bothering to correct it. My next K-5, and current one, was way way better. I was really happy with it. It focuses as well as my K20D, with better image quality. Maybe I don't know where all the focus points line up or exactly how it works, but I can calibrate a lens on a tripod against a chart. I still run into issues where the AF lets me down, maybe it's a skill issue, but it's funny how the AF systems in other cameras, like my friend's 7D, just magically work. The only problem I have with my current K-5 is in very harsh, bright sunshine, I know that washes out contrast, but I don't shoot into the sun and I always use a hood. Stopping down and aiming for the body of the subject doesn't always help. I get as many misses as hits, and they're sometimes wildly off. I don't think my K-5 has anything wrong with it, and I was quite happy with the results until I got the NEX 5N and my keeper rate skyrocketed.
07-05-2012, 09:37 AM   #86
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"I'm getting sick and tired of unreliable AF (rant) "
vs
"I'm getting sick and tired of unreliable AF rant(s)"

Works either way.
07-05-2012, 12:24 PM   #87
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Pentax's AF is notoriously bad compared to high-end Canikon bodies. Especially in low-light.

It's the price to pay for the considerable savings we make on glass and bodies for otherwise good IQ and DR.
07-05-2012, 12:54 PM   #88
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QuoteOriginally posted by Anvh Quote
The -6 and -10 surely do preform the best, what if you stand a bit closer to the wall?
Micro Adjustment: 0


Micro Adjustment: -10


Micro Adjustment +10



QuoteOriginally posted by FrancisK7 Quote
Pentax's AF is notoriously bad compared to high-end Canikon bodies. Especially in low-light.
I didn't realize exactly how much till I once used a friends D3000: Filled the frame with an office seat (the part you place your bum on) covered by black fabric. Only natural light available from the window with drawn curtains. It didn't think much about it. My K-5 on the other hand couldn't do it. I'm not expecting my K-5 be at same level as Canikons, but I expect it to be better than K-x.

Last edited by Zafar Iqbal; 10-29-2013 at 02:05 PM.
07-05-2012, 02:05 PM   #89
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The K5 AF is riddled with problems but it never got the better of me though, i mostly use the AF to get it close and do the rest myself. But the AF is already often close enough so never had problems with it like you're having.

About the photos, not much change when you move closer.
Set the camera on -6 and do some normal shooting, i wonder if that helps...
07-05-2012, 02:24 PM   #90
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K-r! My K-5 is still in for repairs

I'll be shooting all day long at a wedding in 1 days time and it will be very interesting to see how it goes. I'll bring my K-x too, of cause.

This reminds me - I need to dust off my lenses, charge batteries etc.
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