KalNet Message Board

You have some misconceptions. When you say the "zoom" is better, do you mean the Tamron is a better lens? Do you mean the Tamron reaches out further for shooting things like sports or wildlife? Do you mean you assume the 300 mm is the zoom

The best lenses for Canon EOS cameras are Canon, either new or used.

Third party lenses are the third choice in this order of quality:

Tokina, Tamron, Sigma and then the others.

Wedding: 24-70 mm f/2.8
Portrait: 50 mm f/1.4, 24-70 mm f/2.8
Sports: 70-300 mm f/4.5 ~ 5.6, 70-200 mm f/2.8, 400 mm f/2.8, 600 mm f/4.0
Landscapes: 10-22 mm f/3.5~4.5

As you can see lenses are your real investment. Cameras will have to be replaced every three to five years as technology advances. Lenses should last for decades.