I would like to purchase one of these and I'm hoping to get some comments which might help me make a decision. Seen on KEH.com: 18-35 F3.5-4.5 SIGMA ASPHERICAL (82) (FILM ONLY) WITH HOOD, CAPS, 35MM SLR AUTO FOCUS ZOOM SUPER WIDE ANGLE LENS And 19-35 F3.5-4.5 TAMRON (77) 35MM SLR AUTO FOCUS ZOOM SUPER WIDE ANGLE LENS Both of these are used and right in my price range(around 100.00). I don't have much money to spend but I have been wanting a wide angle lens for some time now. Does anyone have any experience with either of these? Does the price seem a bit low for a used lens. According to the ratings both of these are in excellent condition. The primary use will be landscape and architecture work. Thanks for looking.