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09-30-2009, 10:24 AM   #1
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Back- focusing Tamron 70-200 f/2.8

I purchased this lens new a few months ago, but have only begun to use it in low light, i.e. f/2.8, conditions. It's quite obvious that the lens has a serious back focusing problem, and as I'm still shooting with a K10D I have no way of correcting this myself. I guess my question has to do with how much correction can be done in the lens, as in sending it back to Tamron, and how much can be done in camera, as in upgrading to a new K-7. I'm giving serious thought to upgrading, but after downloading RAW files from Imaging Resources and running them through Imagenomics noiseware pro I confess that I'm leaning toward the new EOS 7D which, in my opinion, has at least one stop better high ISO performance. Moreover, most of the reviews I have read say that although the K-7 has improved AF performance it's still not up to par with the Canikons. High ISO performance and continuous autofocus tracking are the two main criteria in my deliberations. I can't see buying a K-7 just to correct this one lens which I'd like to keep along with my K10D, and for a while at least, be a two system shooter. I'm interested in the experience of those of you who have dealt with this problem through Tamron service. Thank you.


09-30-2009, 10:52 AM   #2
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If I were you I would install the debug on your K.10and give that a try, or try a K. 20 it is faster with better lowlight capabilities and quite a bit cheaper than the Canon 7D. Anyways good luck with your decisions.
09-30-2009, 04:46 PM   #3
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If I understand the K10 debug correctly, it adjusts the focus the same amount on every lens you use, kind of a global fix in other words. My other lenses seem to be spot on, and I wouldn't want to sacrifice the quality of several to improve it in only one. Am I correct, or has someone come out with a debug which can be used only individual lenses without having a global effect?

09-30-2009, 04:52 PM   #4
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Good point Clem.
I wonder then whether this is a significant lens issue that ought to be rectified by Tamron (lucky you, you've got that 6yr warranty). It's a very good lens that has been marred by some QC issues.

I'll be sending mine in for a sticky aperture lever...


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f/2.8, iso, k-7, k-mount, k10d, lens, pentax lens, performance, slr lens, tamron
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