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06-25-2013, 05:34 PM   #1
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Tamron lenses after upgrading to K-5ii

I'm curious to know how many of you K-5ii upgraders have had to do any re-calibration of Tamron glass used with previous bodies.

(I'm usually long-winded, so I'm trying to keep this short) I recently upgraded to the K-5ii and I've been doing some casual tests with a Tamron 90mm macro and 17-50mm 2.8. The macro performed wonderfully on a K-7 and, at least at first, on the K-5 original. The 17-50mm was purchased only after getting the K-5, but the two never got along, even after sending both to Tamron for calibration. It turns out there was a big problem with the K-5's AF, and after 9+ months of trying to get it fixed Pentax sent me a K-5ii.

The 90mm macro appears to have a strong front-focus with the K-5ii, so much so that I have maxed out the AF Fine Adjustment setting. The 17-50mm seems to be all over the map, front focusing and back focusing at different focal lengths. Both lenses and the K-5ii will likely have to go to Tamron. If it means getting the 17-50mm working properly I will be happy. When properly focused images from the 17-50mm are amazingly sharp.

It's just weird that the 90mm never had a problem before and my Pentax lenses seem to have no problems going from the previous two bodes to this one.

06-25-2013, 11:29 PM   #2
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the only AF tamron I have is the 28-75 and it appears to be fine on my k5iis and the k5 before it. Hope you get yours sorted out.... I'd be pretty frustrated!
06-25-2013, 11:44 PM   #3
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It IS frustrating, especially considering the small fortune I spent sending things back and forth to Tamron and CRIS (at least 8 trips). I'm willing to do it again if it means the two lenses work as they should.

I won't deny I'm a little wary of Tamron's service department. The first time I sent in the 17-50mm I noted that in addition to the AF issue the aperture blades didn't open completely to an even, circular shape - two blades were basically out of whack. When the lens came back the blades were still out of alignment; ok, no big deal, as long as the AF issue was gone. I've read a lot of lenses have this kind of thing and it doesn't measurably affect image quality. However, when I held the lens up to light there was an insane amount of dust inside. I'm not talking about the three or four particles one mentioned in a Marketplace listing for the sake of being thorough. It looked like somebody knocked over a pepper shaker and put the contents in the lens. The next time the lens went out to Tamron it came back with a zoom ring that made a grinding noise when operated and something rattled around inside...
06-26-2013, 05:47 AM   #4
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Have you tried using CDAF from Live View in critical situations
(like shooting the A16 17-50/2.8 at f/2.8)?

It worked well for me on the K-x
(which doesn't have a regular correction for FF/BF),
and I'm now using the A16 on a K-01,
very happy with the combination.

06-28-2013, 09:31 PM   #5
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QuoteOriginally posted by lytrytyr Quote
Have you tried using CDAF from Live View in critical situations
(like shooting the A16 17-50/2.8 at f/2.8)?
Back when I was trying to figure out what was going wrong with the A16/K-5 combination one of the last things I did was try the Live View AF vs. traditional AF and the viewfinder. It demonstrated to me, and ultimately Pentax Corp., that there was indeed something wrong with the phase detection mechanism. The phase detection system rarely, if ever, got the focus accurate with all the lenses I tested. Live View, however, was perfect every time. This showed that the lenses at least didn't have any issues related to separated elements or harsh decentering.

It's night time now, so I can't test the 17-50mm or 90mm conveniently, but I would expect them to work brilliantly in LV. I rarely use LV (although at times it certainly comes in handy).

I expect what happened with the 17-50mm is Tamron did as they promised - checked over the lens, "fixed" it to Tamron specifications, and then calibrated it to the K-5 - but since it was the K-5 that was ultimately defective I shouldn't be surprised that the zoom is behaving strangely. As I said before, I just think it's odd that the macro is out of whack with the new body when it was fine before and no other lenses show the same issue. *shrug*
06-29-2013, 07:19 AM   #6
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On my K-5 my Tamron 17-50 os AOK but my Tamron 28-75 needs +10 AF adjust for front-focus.
But on my K-x, both are OK with no AF adjust required (or easily possible).

Welcome to the world of variations in lens and body tolerances. There are no faults with either body or lens in either case.

Also it worries me whenever I hear someone say:
QuoteOriginally posted by LowVoltage Quote
I've been doing some casual tests
It's hard to get things right with AF unless you do the testing precisely.
06-29-2013, 03:23 PM   #7
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Tamron and K5

I have the Tamron 17-50 2.8 and it works fine on my K5. What I have noticed is that the value at 17mm is different that the value at 50mm. I set it in between most of the time however if I'm doing a lot of wide angle I'll reset it to the setting that optimizes its performance there.
07-09-2013, 09:49 PM   #8
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QuoteOriginally posted by rawr Quote
Welcome to the world of variations in lens and body tolerances. There are no faults with either body or lens in either case.
I'm not asking if there is a fault. I was asking if anybody had a similar experience, that is all.

QuoteOriginally posted by rawr Quote
Also it worries me whenever I hear someone say:
QuoteOriginally posted by LowVoltage Quote
I've been doing some casual tests
It's hard to get things right with AF unless you do the testing precisely.
Casual test as in, let's walk around the neighborhood with a lens that never worked properly with the previous body to begin with and see what happens. I'm not going to waste an hour with a LensAlign to prove the lens needs +2 when I only need 10 minutes and a brick wall to determine the lens needs more than +10.

07-09-2013, 10:14 PM   #9
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From my own experience, with the brilliant Tamron 28-75 and 70-200 lenses, no adjustment was required, and in fact, focusing has been spot on at 0 fine adjustment whilst with the K-5 classic I had to push the 28-75 to +10 and the 70-200 to +3. Of course, the added bonus of accurate focusing in low or tungsten light with the K-5 IIs made my day shooting with these lenses in concerts and weddings.
07-10-2013, 12:32 AM   #10
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QuoteOriginally posted by LowVoltage Quote
The 17-50mm seems to be all over the map, front focusing and back focusing at different focal lengths.
QuoteOriginally posted by Fauxton Quote
I have the Tamron 17-50 2.8 and it works fine on my K5. What I have noticed is that the value at 17mm is different that the value at 50mm. I set it in between most of the time however if I'm doing a lot of wide angle I'll reset it to the setting that optimizes its performance there.
I had the same problem with this lens and K-5 which I have reported here: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/168617-tamron-...-focusing.html Several members have said they had the same problem. Good news is that in my case Tamron has fixed this. Now the lens has consistent front focus throughout the zoom range which can be corrected by a single AF Fine Adjustment value. And I didn't even have to send the camera body to them, just the lens.
07-10-2013, 01:19 AM - 1 Like   #11
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QuoteOriginally posted by LowVoltage Quote
I'm not going to waste an hour with a LensAlign to prove the lens needs +2 when I only need 10 minutes and a brick wall to determine the lens needs more than +10.
But precision is worth it. Otherwise you end up making posts like these and puzzling over the issue for weeks.
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