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New Contributor
Posts: 2
Registered: ‎06-11-2014

70D + Tamron 18-280

I recently replaced my 60D with a 70D. I like it a lot, However, my Tamron 18 – 280 will not autofocus at longer zoom range, really anything above about 75mm.

 

Any ideas?

 

thanks.

Respected Contributor
Posts: 1,735
Registered: ‎02-28-2013

Re: 70D + Tamron 18-280

Is it not focusing at all, or just poorly?  Does the center point work?

 

I'd guess that the variable aperture lens is passing the max aperture f/5.6 as you're zooming in, and giving the outer focus points (rated at 5.6) some difficulty.  Why it's worse than the 60D, I'm not sure.

 

VIP
Posts: 11,239
Registered: ‎12-07-2012

Re: 70D + Tamron 18-280

"Any ideas?"

 

Yes, it is a Tamron.  It is not uncommon to hear of or have focus problems with 3rd party lenses!  Smiley Surprised

 

EOS 1DX and 1D Mk IV, even less and less other stuff.
Valued Contributor
Posts: 425
Registered: ‎01-19-2014

Re: 70D + Tamron 18-280

 

sage

Valued Contributor
Posts: 425
Registered: ‎01-19-2014

Re: 70D + Tamron 18-280

[ Edited ]

To OP, the Tamron 18-270 mm f/3.5-6.3 ranges from f/3.5 on the short end (18mm) to f/6.3 on the long end (270mm). The D70 has a unique autofocus system which utilizes the sensor pixels for accuracy. Canon has identified certain Canon lenses which have limited compatibility with system.

ScreenHunter_13 Jun. 11 21.25.jpg

My guess is that your lens does not offer full compatibility in part because of the too small maximum aperature of f/6.3 on the long end. This is pretty much the extent of the knowledge I was able to gleen from the web in a short while. Good luck with your work or play.

Respected Contributor
Posts: 1,735
Registered: ‎02-28-2013

Re: 70D + Tamron 18-280

Are you kidding?  Lenses like the 100mm Macro, the 16-35L, the 24 1.4, and a bunch of the long primes?  Those are some quality lenses to obsolete on your new AF system Canon.  Not to mention third party lens troubles.  I'm really surprised, I didn't realize the dual phase system was going to cause issues with current lenses.

Valued Contributor
Posts: 425
Registered: ‎01-19-2014

Re: 70D + Tamron 18-280

[ Edited ]
Full compatibility is not the same as any compatibility. There are certain peripheral auto focus points which might not function as cross points, for example.
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New Contributor
Posts: 2
Registered: ‎06-11-2014

Re: 70D + Tamron 18-280

I'll close this out by saying I talked to Tamron and they assured me that the lens should focus with the 70D, they tested it. I'm sending my lens to them for repair.
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