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06-07-2015, 02:16 AM   #1
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AF Fine Adjustment Saves the Day!

I recently purchased a K-3 with the Tamron 17-50 2.8. When I started shooting with the Tamron, I noticed that none of my pictures were focused properly. In fact, the focus in all of the images was just in front of the main subject, which lead me to conclude that the lens was front-focusing (I might add that I am an experienced photographer). Well, to cut a long story short, the lens required a -10 adjustment! (lucky it didn't need -11 ). So I thought I'd share this story, so that others in a similar situation will not a.) return the camera or b.) return the lens. Below is a picture I took after the AF Adjustment (raw conversion).

https://www.flickr.com/photos/57058404@N00/17934168583/in/dateposted-public/



06-07-2015, 02:38 AM   #2
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I also have a Tamron 17-50 f2.8 that was front focussing, but sadly beyond the fine AF adjustment available on my K5. Happily the Tamron service centre in Perth, Australia (Hartland Camera Repairs) was able to recalibrate the lens with help from Tamron in Japan. It was probably more of a reconstruction that a recalibration, with the whole front element being replaced. It now focusses correctly without fine adjustment and finally lives up to its reputation as an excellent multi-purpose zoom, particularly when stopped down a click or two.
06-07-2015, 03:25 AM   #3
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QuoteOriginally posted by You3andme Quote
I also have a Tamron 17-50 f2.8 that was front focussing, but sadly beyond the fine AF adjustment available on my K5. Happily the Tamron service centre in Perth, Australia (Hartland Camera Repairs) was able to recalibrate the lens with help from Tamron in Japan. It was probably more of a reconstruction that a recalibration, with the whole front element being replaced. It now focusses correctly without fine adjustment and finally lives up to its reputation as an excellent multi-purpose zoom, particularly when stopped down a click or two.
Hi there. Just wondering how much you need to pay for that Tarmon lens re-calibration?
06-07-2015, 04:33 AM   #4
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Hartland's basic charge for recalibration is around AUD100. Mine was a little more, but I found it very reasonable. Apparently straightforward adjustments can be done in Perth by changing chips inside the lens. Not surprisingly they hold a limited number of these devices. So lenses requiring more drastic adjustments may need to be sent to Japan.

06-07-2015, 05:48 AM   #5
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Worth mentioning that that AF calibration is not always just about the lens. Specific lenses and bodies form a pair. Adjustments appropriate for one body may produce different results on another. This complicates things when upgrading, or swapping lenses between bodies.

I have a Tamron 28-75, for example, that has AF that works fine on the K-x, but needs very different AF micro-adjustment (front focus on one, back focus on another) on the K-5 and K-3. Theoretically, a lens should work the same on all bodies, but it never does.
06-07-2015, 06:04 AM   #6
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QuoteOriginally posted by rawr Quote
Worth mentioning that that AF calibration is not always just about the lens. Specific lenses and bodies form a pair. Adjustments appropriate for one body may produce different results on another. This complicates things when upgrading, or swapping lenses between bodies.

I have a Tamron 28-75, for example, that has AF that works fine on the K-x, but needs very different AF micro-adjustment (front focus on one, back focus on another) on the K-5 and K-3. Theoretically, a lens should work the same on all bodies, but it never does.
Yes, I was actually curious as to whether this lens would need the same adjustment on another K-3 body. I would also posit the theory that a few shots in perfect focus (1 out of 10 for example) does not necessarily negate the possibility of a back/front focus issue. Ironically, in such a situation, a perfectly focused shot could be the result of the camera misfocusing (i.e. focusing on something other than what it believes is the intended subject).
06-07-2015, 06:08 AM   #7
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QuoteOriginally posted by rawr Quote
Worth mentioning that that AF calibration is not always just about the lens. Specific lenses and bodies form a pair. Adjustments appropriate for one body may produce different results on another. This complicates things when upgrading, or swapping lenses between bodies.

I have a Tamron 28-75, for example, that has AF that works fine on the K-x, but needs very different AF micro-adjustment (front focus on one, back focus on another) on the K-5 and K-3. Theoretically, a lens should work the same on all bodies, but it never does.
I agree with you on the lens/camera pair calibration to a point that I try to keep it as Pentax lenses whenever possible. I had all my 7 Pentax AF lenses calibrated with my k-5 before the warranty expires in Canada. They wouldn't do it for me if it is a third party lens.

---------- Post added 06-07-2015 at 09:15 AM ----------

QuoteOriginally posted by Charlie70 Quote
Yes, I was actually curious as to whether this lens would need the same adjustment on another K-3 body. I would also posit the theory that a few shots in perfect focus (1 out of 10 for example) does not necessarily negate the possibility of a back/front focus issue. Ironically, in such a situation, a perfectly focused shot could be the result of the camera misfocusing (i.e. focusing on something other than what it believes is the intended subject).
Unless you let the camera chooses the focus point, which experienced users seldom do.
06-07-2015, 06:34 AM   #8
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QuoteOriginally posted by Charlie70 Quote
Ironically, in such a situation, a perfectly focused shot could be the result of the camera misfocusing
PDAF focus precision is such a rich topic for discussion, as hundreds of threads in PentaxForums attest.

Another big AF adjustment variable in Pentax DSLR's used to be the light source. Tungsten light in particular could make cameras like the K-5 front-focus a LOT. I remember the issue well. Luckily, from the K-30/K-5 II onwards, Pentaxes don't have that problem anymore due to design changes to the PDAF sensor. One less thing to worry about.

06-07-2015, 06:38 AM   #9
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Of course, users that let the camera choose the focus point (i.e. beginners) would probably not be familiar with the phenomenon of back/front focus

---------- Post added 06-07-15 at 04:40 PM ----------

QuoteOriginally posted by rawr Quote
PDAF focus precision is such a rich topic for discussion, as hundreds of threads in PentaxForums attest.

Another big AF adjustment variable in Pentax DSLR's used to be the light source. Tungsten light in particular could make cameras like the K-5 front-focus a LOT. I remember the issue well. Luckily, from the K-30/K-5 II onwards, Pentaxes don't have that problem anymore due to design changes to the PDAF sensor. One less thing to worry about.
Back focusing under Tungsten light was a well documented issue with the Nikon D7000 that I used to own - it used to drive me nuts!
06-08-2015, 01:06 AM   #10
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I have sent my K3 and all my lenses to the workshop for calibration. Warranty takes care of the cost. Sweden.
The Tamron has two curves that needs adjustment; One for f5.0 or lower and one for f5.6 and higher.
06-09-2015, 10:39 AM   #11
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Had the same issue with a Sigma 18-250 . The point was that it was not just FF , most of the bright outdoor were blurry and hazy. I thought the lens is covered with dust inside (but it was brad new from the "official import" shop). The lens alone at the shop brought no results. I set a meeting with the service guy which took few shoots with the camera to a lens calibration plate. 5-6 steps with a calibration software on their PC - from Coarse adjustment to fine brought the focus point to "0".
the colors and contrast of the pictures turned into the "expected" quality from that lens.
01-15-2017, 08:12 AM   #12
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QuoteOriginally posted by Tjompen1968 Quote
I have sent my K3 and all my lenses to the workshop for calibration. Warranty takes care of the cost. Sweden.
The Tamron has two curves that needs adjustment; One for f5.0 or lower and one for f5.6 and higher.
Was the Warranty from the Camera or Lenses? I'd like to know if I can do it in Australia.
01-15-2017, 09:19 AM   #13
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QuoteOriginally posted by pentaxkid Quote
Was the Warranty from the Camera or Lenses? I'd like to know if I can do it in Australia.
Well, since it is two years of warranty in Sweden both were under warranty. I don't know how to answer... Buying a new lens and it won't adjust and other lenses adjust, it is the new lens so you will have warranty. Even if the camera does not have warranty the workshop often asks to have the camera also. Sometimes it is the camera-lens combo that acts up.
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