I have an EF-mount Tamron 70-300mm f4-5.6 lens that seems to have developed a problem. On all focal lengths from 70mm to approx. 200mm, the lens works flawlessly. When the zoom ring goes above 200mm, the lens fails to work at any aperture narrower than f5.6.

If I set the aperture to f6.3 or narrower, pressing the DOF preview button does not stop the aperture down. I've tried this lens on both an EOS 30D and a brand new EOS 600D, both cameras hang. The 30D gives me Error 99 and the 600D tells me that Communication between the camera and lens is faulty. Clean the lens contacts.

I have tried cleaning the contacts on both the lens and the 30D, and it didn't help. Does anyone know what is up with the lens? Is there an easy (read cheap) fix or will I have to take the lens to Tamron and get it serviced?

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    \$\begingroup\$ Sounds like it needs to go to Tamron. \$\endgroup\$ Nov 27, 2012 at 12:05
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    \$\begingroup\$ The problem is, that this is a second hand lens I got about 3 years ago for about $100. I'd rather not spend nearly as much as the lens again on getting it fixed. I might as well just get a new one. \$\endgroup\$ Nov 27, 2012 at 12:33
  • \$\begingroup\$ Yes, you might as well. It's a sign! \$\endgroup\$ Nov 27, 2012 at 14:37
  • \$\begingroup\$ Probably failing. I had a similar lens that developed a stuck aperture problem after getting the same issues. \$\endgroup\$
    – RRikesh
    Nov 27, 2012 at 16:37
  • \$\begingroup\$ So does it not work at all or is there a body that On all focal lengths from 70mm to approx. 200mm, the lens works flawlessly.?? \$\endgroup\$
    – BBking
    Dec 7, 2012 at 5:20

1 Answer 1


It sounds like there is some sort of issue with something in the lens. My best guess is that there is some sort of short or loose wire. My second, rather unlikely, guess is that there is something wrong with the blades themselves. Neither of these could be fixed by yourself. Judging from the price that you commented with, you would be better off just buying a new lens, as repairs could easily exceed $100. Sorry that I couldn't offer some miracle solution.

  • \$\begingroup\$ I suspected as much, though I was hoping that there was a magic solution :) \$\endgroup\$ Dec 7, 2012 at 9:06

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