Interesting issue with Tamron Lenses
I received this information a while back, I didnâ€™t post it until there was some kind of response from Tamron.
The following is a direct quote from the folks that found the problem. Tamronâ€™sÃ‚ responseÃ‚ is at the bottom.
i am a member of the german dslr-forum (www.dslr-forum.de), which isÃ‚ probably the biggest german speaking community regarding all DSLR-topicsÃ‚ (not only Canon). We observed a phenomenon where the followings lensesÃ‚ wonâ€™t use the outer cross-type sensors of EOS 40/50/60/7D cameras right.
The lenses that show this problem are (all Tamron):
- 17-50 f/2.8 VC
- 60 f/2 Macro
- 70-200 f/2.8
- 10-24 f/3.5-4.5
To get a bit more into the detail of the problem â€“ on the 40/50/60DÃ‚ cameras the outer cross-type sensors only work as line-type sensors. ToÃ‚ be a bit more correct, they actually work in the same direction as theyÃ‚ would work on cams like the 30D or like the 400/450/500/550D. When itÃ‚ comes to the 7D the outer sensors are also only working as line-typeÃ‚ sensors (but it seems, that the EF 50 1.2L also has problems to use themÃ‚ correct).
The center cross-type sensor does work at least as a single-cross typeÃ‚ sensor (infact we donâ€™t now how to test if the center sensor is workingÃ‚ as a dual-cross-type sensor like itâ€™s supposed to work with those f/2.8Ã‚ and better lenses).
Tamron seems to not know about this behaviour so far. Well â€“ at least,Ã‚ they didnâ€™t confirmed the problem and only said, that they willÃ‚ investigate this.
Maybe a small addition â€“ the Tamron 17-50 VC uses the same lens-ID asÃ‚ the EF 35-80 â€“ maybe youâ€™ll have the chance to check whether thisÃ‚ Canon-lens performs correctly or not.
The link to the thread is:Ã‚ http://www.dslr-forum.de/showthread.php?t=732360
Tamron Europeâ€™s Official Response
Dear Mr. S.,
we were able to reproduce the situation where the Tamron 17-50 VC (B005)Ã‚ and the Tamron 60 Macro (G005) wonâ€™t use the Canon EOS 50D cross-typeÃ‚ sensors correctly.
We have given this information to Tamron in Japan and we are expect anÃ‚ answer very soon.
Tamron Europe GmbH