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03-25-2012, 09:33 AM   #1
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K-5 AF Issue

I've been pulling my hair out, but I finally think I found my problem with my K-5.

Back about 3-4 weeks ago, I purchased a DA*55 new. My first day with it was quite frustrating as I was getting severe back focus issues. After spending a couple hours with the AF fine adjustment, even at +10 it was still back focusing. So the lens was returned as defective.

I've used other fairly sharp lenses last fall without any problems - DFA 100 2.8 Macro and FA* 300 4.5 - was getting perfectly sharp images.

Today I mounted my DFA 100 lens, and after a short shooting session when reviewing my photos, they were 90% out of focus. So, back to the AF fine adjustment procedure until I came to +8 where the images were nice and sharp. Now I get to wondering what is going on.

To test a bit farther, I mounted my newly acquired DFA 50 2.8 Macro lens - the same drill - 90% out of focus. So I then set the camera to AF adjustment for ALL LENSES to +8 and all is good again.

Now I believe that with the DA*55 lens, if it needed a +3 or +4 correction which would be in factory tolerances, I simply couldn't go that far since my body seems to be off by +8 to begin with.

My next step just to finish my testing is to test these lenses on my K-x to see how they work.

I've done my forum research, and have read that while this isn't a common problem, it is one that exists. So, no huge deal - I will send it in to CRIS for repair. Man am I glad I have a back-up body!

One question for those of you who have sent their bodies in for this type of repair - did you include a lens when you shipped it to CRIS? I was thinking I should send it in with one of my sharper lenses for the calibration process.

I've been pulling my hair out for the past 2 days trying to figure out what was going on - I feel a bit better now that I have narrowed the issue down to the camera not focusing properly in AF mode.

I'll be packing the camera up today to ship - any other suggestions before I send it off tomorrow morning?

Thanks

03-25-2012, 09:39 AM   #2
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The sensor actually drifted out of focus? That sucks!
Send it CRIS, but give them a call to explain the problem and ask if you should include a lens they can calibrate to. No sense risking a lens in transit if you don't have to.

BTW, if this change in AF adjustment happened roughly when you got your FA*300, I think you should consider that lens the culprit and send it to me "for further investigation" on my K-5.
03-25-2012, 10:04 AM   #3
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Good idea about calling first - I am thinking they might have a standard calibration method of their own to use without the variance of using a "used" lens.

Well, since I am going off the deep end with this issue, I just did in fact take the FA*300 out for a spin with the camera set at +8 for all lenses. And here I thought that lens was sharp before.......oh my god! I'm so glad I am going through this as I am just floored by how sharp the images with this lens are now.

I've also now tested with my trusty DA 55-300 - very nice results. Actually I am thinking of just living with the fact that the camera is set on +8 and not send it in......but in the end I think I will.
03-25-2012, 10:10 AM   #4
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I am on my 3rd K-5. While my first 2 K-5 bodies exhibited the following behavior, my current does one not. I do not know if it was hardware or firmware related.

The first two K-5 bodies I had would change AF adjustment tolerances just by enabling AF adjustment, even if no actual adjustment was made. That is, (EDIT: some) lenses that needed no adjustment, all the sudden were out of alignment when AF adjustment was turned on. These were factory fresh bodies. I never was able to address this issue with complete success. My current K-5, whch I purchased used, does not have this problem.

I am not sure if this applies to your situation, but I thought it worth mentioning.


Last edited by apisto; 03-25-2012 at 12:52 PM.
03-25-2012, 10:18 AM   #5
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Hmm... next time we get a rainy weekend, I'll break out the LensAlign and re-test some of my faster glass. Thanks for making me curious, stormtech and apisto!
03-25-2012, 02:15 PM   #6
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OK - somebody slap me!

After spending the whole day test shooting - adjusting - on the tripod - off the tripod - printing out lens charts - outside testing - back inside testing.......my wife just watching me go out of my mind - is this what they call OCD?

Anyway, I thought I would test each of my lenses separately just to be sure. Between using the lens chart with tripod and 2 sec timer, the primes all zeroed in with +8. With the zooms however it was hard to tell the difference between adjustments. I also did some real world testing on a wooden birdhouse outside where the +8 worked well with all but the 16-45 which seems to be sharper in the real word test with no correction.

I now have to put all my toys away as my wife is finally getting disgusted with me I think.........
03-25-2012, 02:28 PM   #7
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QuoteOriginally posted by stormtech Quote
is this what they call OCD?
Yes. Your wife is being very tolerant.

While you are going all OCD, you may as well actually buy something like a Datacolor Lenscal just to perhaps make your AF checking process easier and more consistent.
03-25-2012, 02:33 PM   #8
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My guess is they are probably fine and you should turn it off and set to zero !
The problem is the focus points ! My guess is that you use the red square ? If you do... thats the problem.
The sensors themselves are actualy huge. The centre sensor is pretty much the same size as the two semi circle markings for spot metering.
If then you are trying to say be critical and focus on the eye, the sensor can pick up on the nose or ear or even miss altogether and focus on the background.
Now think about this ! If it focuses on the nose, you assume front focus.... the ears... back focus... background.... focus failure !
You can find this and see for yourself, quickly and simply by putting a dot on peice of white paper and slowly move the camera around it and see where
it reacts from. Super fast lenses are not easy to use on K5 because of this. See the semicircle as your focus point and you will see a big differance.
I hope this solves your problems.
PS... for critical work I would go manual.

03-25-2012, 02:49 PM   #9
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I am seriously thinking of a Lens Cal system, but I think it might just add to this OCD.

westmill - I read your post and I am listening. It seems that this issue is possibly just showing itself now as I am acquiring some sharp lenses. I've mostly just used the 16-45 and 55-300 over the past year. I only acquired the FA*300 in January and am just now starting to really use it since the weather has turned warm. Also I've had the DFA 100 since last fall, but that also didn't see much use over the winter.

But I do see a definite difference in my real-world testing when I have the adjustment to +8 on all the sharper glass.
03-25-2012, 02:58 PM   #10
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The shallower DOF of the fast lens is more critical while the slower lenses are covering some of the dof with the smaller aprature.
Seriously.... when you test your focus.... how do you know where it is even focussing ?
Take a look at my pics ! there is an album called AF or summit !
Lots of people have this issue... including me, until i discovered the problem.
I bet everyone of your close ups are sharp arnt they.... thats because your focus target is then bigger if say its an eye.
Trust me on this one and check it out. Unless you knew the focus point is the size of the semicircle of course and you are already aware !
03-25-2012, 04:00 PM   #11
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If you do send it in request a "AF calibration". CRIS does the calibration with a "Master Ref Lens" so they don't need you to send in a lens unless you have one you want checked out.

If you send it in to get calibrated you wouldn't need any global adjust and any specific lens should fall well under previous fine adjust. Your call.
CRIS tech did a very good job calibrating my K5 and repairing/fine tuning my DA 12-24. I just leave my AF fine adjust "off" now. I have "Lens Align" new in box so eventually I will see if I can improve some of my lenses or not.

P.S.--Your K20D is being well loved my me. Nice to have second setup/backup. Also I believe I hold the record for your fastest transaction----from listing to mail lady!
03-25-2012, 04:24 PM   #12
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Thanks for your input jcp5 - yeah that was the fastest transaction yet - I think it was within 5 minutes of selling, paying, & shipping!

While I give credence to what westmill is saying, some of my tests today involved an old wooden bird house. When shooting this with the 100mm lens, the entire center circle in the viewfinder was on the bird house surface. I thought I would try to post an example here - don't know if it will show the differences as well as on my monitor, but here goes:





These are with the DFA 100 2.8 Macro WR lens.

The first image is with no AF adjustment - the second is what I ended up with at +8 adjustment.

Thanks for the info about sending in the body only to CRIS jcp5 - being the K-5 is under warranty, I'm going to send it in if for no other reason to check my own sanity at this point. If they say they calibrated it - great! If they say there is nothing wrong, then I will know what I have to live with and can get on to bigger and better things.
03-25-2012, 04:27 PM   #13
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This whole thread makes me very nervous... I will be getting my K-5, with 100mm DFA WR. With all this AF issue, I guess I have a tough time ahead calibrating all my lenses ... :-(
03-25-2012, 05:10 PM   #14
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Well I certainly didn't post this to make you nervous! I've done a lot of research on this issue and it seems to be very isolated.
03-25-2012, 06:14 PM   #15
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stormtech--- Glad to see you are sending it in for calibration while it is under warranty. You don't have to worry about CRIS saying there is nothing wrong----they will do the cal because it is faster. If there is anything more to it they will repair. Make sure you record your "USER" settings because they will clear them. Take out your memory card and battery before sending in. If there is anything else you think isn't right put it on your repair form, no matter how small or random and the tech will check it.

vsmouli--- This isn't a AF design defect ----It's just bad calibration/QC when manufactured. Luck of draw. Make sure you buy the Pentax 2 yr extended warranty for $20 because it is such a good deal!

Last edited by jcp5; 03-25-2012 at 11:12 PM.
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