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AF adjustment on K-7 (maybe K-5 too)
Posted By: jaeaetee, 08-17-2013, 09:41 AM

Here's some help if your K-7 needs AF adjustment (run out of AF fine tune range). Seems quite simple, there are same kind of screws in same locations as with the K10D (for which one can find service manual from the net, Downloads).

There's one difference however; with K10D/K100D it's enough to just remove bottom plate, but in the K-7 the "third" screw (C adjusts front/back focus) is under the front cover (maybe they thought that fine tune is mostly enough..). Image from the RiceHigh's blog: RiceHigh's Pentax Blog: Hardware Adjust a Pentax DSLR for the AF.

1. To remove bottom plate, just unscrew all visible screws. Two of them are under battery door.
2. To loosen the front cover, I would also recommend unscrewing the top cover (neither cover needs to be completely removed). So all visible screws again, but there's one deep in the battery cavity, two behind the eyecup, two under the pop-up flash and one under the left grip. Lens mount bayonet does not need to be removed!
3. Once all screws are removed, the front cover should come out just by pulling it gently and pulling downwards slightly at the same time. The lens removal button and AF mode switch will come with it, so no worry about them. Note: AF switch will have to be in the same setting/location as when the covers were still together, otherwise the front cover doesn't go back in place.
4. I adjusted the "C" screw about 45 degrees clockwise to fix back-focus. This translated to about 4-5 steps of AF fine-tune from the menu. So, no big adjustment needed, careful with it..
5. For the work, you'll need preferably a "JIS" standard screwdriver (almost the same as #00 Phillips) and a 1,5mm hex tool.
6. Careful with wires. See the pictures, my camera had the one blue wire scratched against the tripod mount (sharp metal edges), probably by a service man (I had the thumb wheel warranty replaced) or already in the factory..




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12-01-2013, 07:47 PM   #2
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Thank you for the information...I too have a K-7 and have "max'd out" on adjustment to correct back-focus. From the photos, am I correct that when turning the screw clockwise the camera lens mount is facing you?

Again, thank you!

Manuel
12-06-2013, 07:59 AM   #3
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QuoteOriginally posted by marosari00 Quote
Thank you for the information...I too have a K-7 and have "max'd out" on adjustment to correct back-focus. From the photos, am I correct that when turning the screw clockwise the camera lens mount is facing you?

Again, thank you!

Manuel
The procedure works! In my case, it took two adjustments to bring the camera "into focus". Thank you "jaeaetee" for sharing the information.
01-07-2014, 10:15 PM - 1 Like   #4
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Hi and glad that it helped!

03-01-2014, 12:19 PM - 1 Like   #5
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Update for this topic..

I almost never use other than middle focus point, so I didn't notice one thing: adjusting the AF using the one screw "C" (bottom right screw, when lens mount is towards you) of course will introduce some tilt to the AF sensor. Stupid me

Solution: just adjust all three screws same amount. But if the AF sensor is tilted (i.e. camera back- or front-focuses depending on which AF point is used), the screws seem to work "reversed" compared to the viewfinder image. So, if you have back-focusing with the rightmous AF points, adjust the left screw (screw "A" in the photo above) to correct it. Clockwise to bring focus closer.

Also seems that the Pentax build can withstand multiple dismantlings quite well. I have done it now 3 or 4 times for my K-7, first just out of curiosity, then AF adjust and now again to correct that annoying tilt.

Note that one should use a good lens to adjust AF. I noticed that my 35mm limited macro has a tiny amount of focus plane tilt and the 21mm limited wide-angle has too much curvature of field (or something), resulting non-consistent auto focus. I used the 100mm D-FA macro lens to adjust AF.
10-01-2019, 05:30 PM   #6
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QuoteOriginally posted by jaeaetee Quote
Here's some help if your K-7 needs AF adjustment (run out of AF fine tune range). Seems quite simple, there are same kind of screws in same locations as with the K10D (for which one can find service manual from the net, Downloads).

There's one difference however; with K10D/K100D it's enough to just remove bottom plate, but in the K-7 the "third" screw (C adjusts front/back focus) is under the front cover (maybe they thought that fine tune is mostly enough..). Image from the RiceHigh's blog: RiceHigh's Pentax Blog: Hardware Adjust a Pentax DSLR for the AF.

1. To remove bottom plate, just unscrew all visible screws. Two of them are under battery door.
2. To loosen the front cover, I would also recommend unscrewing the top cover (neither cover needs to be completely removed). So all visible screws again, but there's one deep in the battery cavity, two behind the eyecup, two under the pop-up flash and one under the left grip. Lens mount bayonet does not need to be removed!
3. Once all screws are removed, the front cover should come out just by pulling it gently and pulling downwards slightly at the same time. The lens removal button and AF mode switch will come with it, so no worry about them. Note: AF switch will have to be in the same setting/location as when the covers were still together, otherwise the front cover doesn't go back in place.
4. I adjusted the "C" screw about 45 degrees clockwise to fix back-focus. This translated to about 4-5 steps of AF fine-tune from the menu. So, no big adjustment needed, careful with it..
5. For the work, you'll need preferably a "JIS" standard screwdriver (almost the same as #00 Phillips) and a 1,5mm hex tool.
6. Careful with wires. See the pictures, my camera had the one blue wire scratched against the tripod mount (sharp metal edges), probably by a service man (I had the thumb wheel warranty replaced) or already in the factory..

Could this adjustment be better done in software via the debug menu?
My *16 - 50 f2.8 needed more than 10 points of focus adjustment on my k-3.
Via the debug menus I added 60um of af adjust then re tested the lens.
It now focuses spot on with only 7 points.
All my other lenses then Needed re-calibration and had shifted by roughly the same amount, in the same direction
07-26-2022, 11:15 PM   #7
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QuoteOriginally posted by ryan63 Quote
Could this adjustment be better done in software via the debug menu?
My *16 - 50 f2.8 needed more than 10 points of focus adjustment on my k-3.
Via the debug menus I added 60um of af adjust then re tested the lens.
It now focuses spot on with only 7 points.
All my other lenses then Needed re-calibration and had shifted by roughly the same amount, in the same direction
If the AF-adjustment in the camera is on its limit I think this method is better, otherwise one might not be able to adjust for all lenses.

The same applies for the K30/50 (from page 44 onwards) shown in the service manual:
Pentax K-50 / K-500 Service Manual + Parts List - PentaxForums.com

The original article in Chinese can only be found here via wayback-machine:
https://web.archive.org/web/20160328053049/http://www.cnpentax.com/thread-24-1-1.html


Last edited by photogem; 07-26-2022 at 11:21 PM.
12-23-2023, 09:15 PM   #8
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I need this service done on a k3 III in the USA … does anyone know what listed repair store on the forums is the most affordable … Thanks
12-27-2023, 12:46 PM   #9
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So I have a failed k3, likely mainboard I disassembled to learn / try to fix … I took off the top to clean the power switch … hell marry … camera still doesn’t turn on … but took some pics and I would rate disassembly process / focus adjustment to be easier than fixing a modern day iphone.

Resources used for info
Tutorial: Repair E-Dials Pentax K5 (also K7/3 etc.) - PentaxForums.com


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