Canon has been an industry leader in digital photography, and this has mainly been because of the number and quality of lenses which are available. I will admit that the first lens I purchased for my EOS-10D was a Tamron 28-75 F/2.8 DI which provided excellent pictures at an amazing price. In order to afford the Canon 24-105 which I'd read good reviews about, I sold the Tamron as well as the Canon 50mm/1.4 which is was an even sharper lens, though obviously a prime which has it's pros and cons.
APPEARANCE
The Canon 24-105 is a very nice looking lens with a solid feel, though it doesn't feel much heavier than the Tamron and is certainly much lighter than the industry standard Canon 24-70 L lens which many are now off-loading to purchase this lens. The craftsmanship is top-notch and I found no concerns here.
FOCUSING
This is an area where this lens truly shines. Usually people just assume an ultrasonic motor is an ultrasonic motor, but this lens focuses faster the my 50/1.4 USM prime. Focusing is flawless and consistent.
PICTURES
I haven't had much time to really do comprehensive testing and comparison, but the clarity is amazing straight out of the camera and even better after photoshop. Colors are vivid without major CA.
