Tamron autofocus not working?

[Mylkinut]

Hi all - new here and coming back to photography after a long hiatus!

I recently bought a Canon 500D second hand, and the seller was kind enough to throw in a Tamron 28-200mm lens to sweeten the deal. However, the reason he gave it to me was because the AF is dead. He said it just stopped working one day, and while it's not the best lens in the world it'd be nice to get it working if I can. My other lens' AF works fine, so I know it's not the camera body.

Having looked at it, these are the symptoms as I can see them:

• Lens autofocus doesn't respond to the camera - even when the lens is set to AF, the camera acts as if it's set to MF (it even displays 'MF' on the screen).
• MF on the lens works as intended - nothing's stuck and you can adjust the focus ring freely.
• Switching the lens to AF engages the motors in the lens - the focus ring offers resistance when set to AF, as I presume it should.
• Aperture controls still work fine - seems the camera can still communicate with the lens for this.

It feels like the problem isn't mechanical but electrical. Would cleaning the contacts on the lens be worth a go? They look pretty spotless, but I can order some isopropyl alcohol if it's worth a try. Otherwise I guess I'll just consider it a MF-only lens!

Any help would be appreciated, and sorry in advance for my newbie-ness - it's been about 7 years since I used a DSLR in anger so I'm a bit rusty.

Cheers!

 

[ChrisH]

You can clean the contacts with an ink deraser just be gentle. More likely the lens has a fault as you usually get error 9 with bad contacts. It's not worth trying to have it repaired it will cost more than its worth. Before you do much factory reset the camera it may just have a daft setting like back button focus set in it. I fell into that trap when Canon sent my 1d3 back after repair with some of " their " settings in it including back button focus which I never used.