Canon 17-55 vs Tamron 17-50

Introduction

The Canon 17-55 is a very good lens, you can check the review of the lens at the review section. It has very good sharpness, nice colours and contrast. Don’t be fooled by that it has not an “L” designation. Up to now no Aps-C lens has “L” sign, seems it is some kind of marketing strategy from Canon to influence people towards Full frame cameras.
Is it worth to buy the name brand ? How these two lenses perform optically? Which has the better value? I seek answers to these questions in this article.

See the samples below, all picture on a tripod:
Settings Canon 30D camera 3504*3336 8 Mpix jpg resized to 1200 pix

Canon 17-55 f/2.8 is	Tamron 17-50 non VC

Aperture : f/2.8	Aperture : f/2.8

Aperture : f/5.6	Aperture : f/5.6

As I see it:

The biggest difference between the two lenses are the price.

If we don’t think about the price the two biggest difference between the two lens is the USM drive and the stabilizer in the Canon lens. Although the Tamron has a new stabilized version as well.

The Canon 17-55 is is sharper at f/2.8 significantly
At f/5.6 at the peak both very sharp
The Canon has better contrast
The Tamron is a very good value, and sharper in the corners, and also wider at 17mm setting.