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08-23-2013, 12:09 AM   #1
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Third party zooms

I have tried two examples of Tamron's 70-200 f2.8 and using a focusing chart have found they both front focus at 200mm and back focus at 70mm. Obviously in camera fine autofocus adjustment will not be able to adjust for both.

Does anyone have this lens or third party zooms who say this is common, acceptable or otherwise.

Is this something we have to accept with third party zoom lenses. I in two minds whether to sent it back for a refund.


Regards

Jeff

08-23-2013, 05:54 AM   #2
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Don't do that, send it with your camera to Tamron for adjustment. They can fix it, and it really is worth it. An absolutely amazing lens. Also, be careful of the light you are using. If you do focusing chats with tungsten lights, you get odd behavior. Use only natural light for focusing charts.
08-24-2013, 12:01 PM   #3
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Just took some real life images with it and its really sharp, but not where I want it to be. It would really be a fantastic lens but for this problem.

Anyway I have boxed it up and I'm sending it back. I have asked for another one, third time lucky I hope.
08-24-2013, 12:08 PM   #4
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Mine does that. I've compensated by adjusting it to focus accurately from 70-135mm, and then hoping I hit good focus on the 200mm. After about 6 months of using it that way, I generally get things in focus (for example, knowing it backfocuses at 200mm, I adjust a bit).

But it is a flaw and I would send it in if I still had warranty.

08-25-2013, 04:53 AM   #5
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Amazon uk want to refund my money as they think there may be a batch problem. They had this lens 100 cheaper then anywhere else in uk and I expect they will revert to there previous price soon. I haven't sent it yet so I could keep it then send it to Tamron. I will think about it for a couple of days. Could get a Sigma instead I suppose.
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