I can observed that photographers are long to grab a Tamron 17mm-50mm F2.8. Believed that at that kind of price getting a F2.8 lens is consider cheap . And I also found out today that some people willing to give up their canon 17mm-40mm F4 L for this Tamron lens.
Hmmmm......I owned the canon lens and it had served me good. I see no reason why one will give up this canon L lens just for a F2.8 3rd party lens.
I'm just curious and wish to hear views towards these 2 pieces of glasses. Hope no offends