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04-16-2015, 10:28 PM   #1
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How much do you micro-adjust AF setting [Menu->All]?

I lost my patience when trying to micro-adjust AF for each of the lenses (four zooms, one prime).
I've ended-up with solid +8 menu micro-correction in K-3 body.
No consistency from time to time, some back-focussing still happens, with almost none front-focussing.
What's the point that most of the Pentax users report back-focussing (front focussing seems to be in a very minority) and Ricoh/Pentax/Asahi don't do anything with that issue in-factory?
Is that some internal parts within the body get loosen in such a way, they cause back-focussing (no front-focussing)? Is there no way to fix it in a camera design (we''ll Loctite them all)?

04-16-2015, 11:29 PM   #2
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I adjust mined individually by each lens. My Pentax lenses are all really good, maybe +2 on my DA35 but my Tanny 18-200 is a +8 but now extremely sharp at that adjustment. Zoom lenses are a little harder than primes, you will have to compromise since it is a range of focal lengths to adjust the midpoint.


Once adjusted, I haven't had a problem to readjust but in time, I would assume that it can happen to test again. Keep in mind that many things can occur that will cause you to be out of adjustment from pic to pic, namely lighting in the photo.
04-16-2015, 11:37 PM   #3
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Have you a different micro adjustment for each lens? My K3 had a bias towards the minus scale and the Sigma 50-15mm needed more than -10, finally I sent it in for repair and asked them to adjust the AF again, when it came back the Sigma need -7 so all was well.
It sounds like yours needs recalibrating by Pentax!
04-17-2015, 12:56 AM   #4
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I know that.
I guess this is the way company makes profits:
When I send my K-3 to the service center, as they'll repair my camera for the next 4 months I'll need to buy second body at least for that time.
Ingenious marketing practice!
I hope at least EU shall force camera-makers to use common bajonett-mount in the near future, so one can buy temporary Canioly EU (stands for Easy Unified) body for our collection of Ripeas EU lenses


-----
QuoteOriginally posted by Dave's clichés Quote
It sounds like yours needs recalibrating by Pentax!



Last edited by Prakticant; 04-17-2015 at 01:23 AM.
04-17-2015, 01:05 AM   #5
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QuoteOriginally posted by Prakticant Quote
I lost my patience when trying to micro-adjust AF for each of the lenses (four zooms, one prime).
I've ended-up with solid +8 menu micro-correction in K-3 body.
No consistency from time to time, some back-focussing still happens, with almost none front-focussing.
What's the point that most of the Pentax users report back-focussing (front focussing seems to be in a very minority) and Ricoh/Pentax/Asahi don't do anything with that issue in-factory?
Is that some internal parts within the body get loosen in such a way, they cause back-focussing (no front-focussing)? Is there no way to fix it in a camera design (we''ll Loctite them all)?

I'd had to do the +10 max adjustment for my k3 across the board for the da* zoom lenses I owned and was still not getting a sharp image, seemed to still back focus. Sent the body and the da*60-250 back to Pentax to check and was advised that the body was so far out of adjustment it would not have been possible to correct it with micro-adjustments on the camera.

I'd asked the service dept in Australia if this was a common issue and he'd mentioned that a few had the same issue, wouldn't give me any numbers though.

Needless to say, now the camera and the lenses I have are tack sharp.
04-17-2015, 03:38 AM   #6
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QuoteOriginally posted by Prakticant Quote
I lost my patience when trying to micro-adjust AF for each of the lenses (four zooms, one prime).
I've ended-up with solid +8 menu micro-correction in K-3 body.
No consistency from time to time, some back-focussing still happens, with almost none front-focussing.
What's the point that most of the Pentax users report back-focussing (front focussing seems to be in a very minority) and Ricoh/Pentax/Asahi don't do anything with that issue in-factory?
Is that some internal parts within the body get loosen in such a way, they cause back-focussing (no front-focussing)? Is there no way to fix it in a camera design (we''ll Loctite them all)?
Both camera bodies and lenses are made to a +/- manufacturing tolerance. It's the combination of those tolerances that result in back/front/perfect focussing, so you might get back focussing when lens A is on body A, but perfect focus when lens A is mounted on body B, etc.
04-17-2015, 06:03 AM   #7
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QuoteOriginally posted by JohnX Quote
Both camera bodies and lenses are made to a +/- manufacturing tolerance. It's the combination of those tolerances that result in back/front/perfect focussing, so you might get back focussing when lens A is on body A, but perfect focus when lens A is mounted on body B, etc.
Does the camera remember the adjustment on a global basis or a lens basis???
04-17-2015, 06:44 AM   #8
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QuoteOriginally posted by jgnfld Quote
Does the camera remember the adjustment on a global basis or a lens basis???
Either. You have an 'all' or 'one' (or something similar). The 'all' will apply the same adjustment to every lens; the 'one' per lens.

Note, though, that the lens has to be modern, insofar as it will contain an internal electronic id that the camera reads and stores in a database (of up to 20 lenses I think). So old manual lenses won't be recognised.

Also, it works best with Pentax lenses. Non-Pentax lenses don't always have a Pentax-format recognisable electronic id, or may use generic id's.

Search for 'AF fine adjustment' on here and other Pentax related forums; there's plenty of advice and guidance our there, especially on the best way to recognise front/back focussing issues and how to determine how much adjustment your body/lens combo needs

04-17-2015, 11:02 AM   #9
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Tired of AF focus adjusting. SO nowdays I keep it off as default and when there is problem with focusing I try to adjust AF correction...
04-17-2015, 12:50 PM   #10
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One thing; if you are going to adjust your lenses, make sure you do it properly. There are several threads and articles on this both on this site and elsewhere. Use a tripod, use a properly aligned target at a sensible distance (depending on the focal length). Any other way introduces too many possible sources of error and may well end up making any faults worse.

That said, I must either be very lucky or not very picky when it comes to focusing. I have checked, but not found it necessary to adjust any of my lenses, neither on my K-3 nor my K-5.
04-17-2015, 10:51 PM   #11
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I tried that 'proper and scientifical' way, but it did not make sense with zoom lenses without access to the camera body service mode (and adjusting focus point by focus point).
I finished making portraits and after 1:1 pixel studying at computer screen, adjusting micro-setting step-by-step for model eyes (lashes) to be sharp (front eye).
As for DA* 16-50mm/2.8, DA* 50-135mm/2.8 and DA* 200mm/2.8 the setting seemed to be similar (+8/+9), I ended-up with camera body menu All setting +8.
That convinced me the problem was (is) camera body rather than lens/lenses (I used to have only one DA* 16-50mm at the begining).
I am not sure if camera remembers serial numbers of the lenses, or just a lens type - I have two of 16-50mm (older secondhand one which I initially blamed to be out of focus, and the new retail one got on sale) and two of 50-135mm (one in service).
I'll have to confirm the micro-adjustment with DA 12-24mm/4, at least fully open f=4 at 24mm long end.

-----
QuoteOriginally posted by savoche Quote
if you are going to adjust your lenses, make sure you do it properly. There are several threads and articles on this both on this site and elsewhere. Use a tripod, use a properly aligned target at a sensible distance (depending on the focal length). Any other way introduces too many possible sources of error and may well end up making any faults worse.
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