Sigma 170-500mm F5-6.3 APO Aspherical Lens for Pentax-AF Camera

Rating:
Summary: Best lens for the money!!!
Review: I purchased this sigma 170-500mm lens about 2 mos ago, and was very impressed with it from the start! The lens has a good feel to it! not very heavy, but well built! The only thing I would change is the manual focus ring! it is a bit loose and hard to micro adjust! after about a week of practice, I think I have mastered it. Now the important part! picture quality! I have used this lens to photograph birds, deer, seals, and zoo animals, every time the pics came out clear and sharp even at the edges. I sometimes use a Kenko 2X converter to bring my zoom to 1000mm and still get sharp pics! I've owned Canon lenses in the past and was very happy with them also, but Sigmas photo quality is very close if not eaqual to any comprable canon lens! why pay 2-3-4 times more??? I curently own 4 sigma lenses "20-70mm, 28-105mm, 70-300mm, and 170-500mm" and am very happy with all 4 lenses! the true test will be when you strap it onto you canon,nikon, or any oter camera you own and see for yourself.