http://www.nikonchat.com/sigma-nikon-lenses/

And sell my Nikon 18-135 lens Sigma 50mm/f1.8 case and get 30mm/f1.4 as my only goal?
I would love to get that but I have no money sigma now. Do you think I'll be able to use a lens first and my only goal? Ar Nikkon the two lenses worth selling? (Incidentally, that means that I D40x my 50mm lens does not autofocus)
The point of buying a nikon digital slr is to get the big Nikon glass. Selling two Nikon lenses to buy a brand Lens-off sounds a little silly to me. I at least keep the 18-135, just by how useful it is. Primes are great, but not so practical for everyday shooting. I really miss having him be expanded. My advice is that if you really want to, save for it, and think that then. Not only will you have a better arsenal of lenses, but thank you a lot more because I had to work for it.
Sigma 70-200mm HSM dslr lens Review by Dom Bower