So I read about lenses and learned about wide angle lenses. And one of the best selling canon wide angle lenses is the 17-40mm f40. I bought one at a discounted price expecting so much from it. To my frustration, I should have bought high end digital camera with wide angle lens instead. Well, i believe this can be a good lens depending on the subject of interest, only its not useful to me at this time.
Suddenly I like my Canon 50mm, it can do nice portraits easily and is much sharper than 17-40mm.