The internal focusing is fast and accurate at F4.5-5.6, and full aperture is perfectly OK in the centre of the field.
Distortion is the big issue with a lens like this. Does it yeild straight lines in room interiors at 11mm?
In short, it does. it delivers professional quality geometric projection with hardly any illumination fall-off.
It is an amazingly good design, it is more convenient than bulbous non-filter compatible lenses . . .
F2 FREELANCE & DIGITAL. AUGUST/SEPT 2005

The Tamron 11-18mm offers superb value for money
and has to receive our Best Buy award.
Wide Angle Zoom Comparison Test
May 2006

Verdict: this is a fine ultrawide lens for the DSLR owner and most users are unlikely to be disappointd.
Pros: Optical performance, lightweight, contrast

Handling: 20/25
Features: 22/25
Performance: 23/25
Value for money: 23/25
Final Score: 88/100
Wide Angle Zoom Lens Test - Photography Monthly
June 2006