I'm a newbie and recently got a Sony DSLR A200 with the included 18-70mm f3.5-5.6 lens. Although I can take pictures with the lens I feel that it is somewhat limited and I'm looking to expand. What I like is extremely soft pictures with a short DOF. I also dislike flashes. Therefore I figured that a lens with an extremely low F number would suit me but there doesn't seem to be any available with zoom. They always seem to be fixed at 50mm. Is there a lens with zoom? Budget: somewhere around 500USD. The less the better.