Gets the job done for a great price. Requires skill to get good results.
2 December 2011
Summary: Using on a Canon 60D Definitely best for use as a Macro lens. Bought it with intention of using it as cheap, multipurpose, fast glass. Works great in brilliant sunlight, not as sharp in low-light. It gets the job done and at an extremely reasonable price. Works wonderfully for up-close video! I wish I had put out extra money for sharper glass, though I'm not completely dissatisfied with this purchase as it does get the job done for portraits and general purpose.
Summary: I like using this lens for all the times my family is sitting at the kitchen table or playing in the living room. It enables me to go without flash most of the time in those situations. However, it is also a very fine lens for those times when I want to be a "serious hobbyist." It does macro as well as a dedicated 1:1 macro lens that I recently owned. I also own a sigma 50-150 and it is also very nice. Together the 2 cover the field for me.
Summary: Lens is fast and images are rendered sharp. Bokeh at f4 is just awesome. HSM motor really delivers and its quiet, really quiet. Love the weight on the lens and it sits proudly on my kx unit. Would recommend this lens to anyone who is looking for a good short tele range.
Summary: The Sigma 70mm f2.8 DG EX macro is among the best 4 best macro lenses in the world: Canon 100mm f2.8L IS, Nikon 105mm f2.8 VR Micro and probably the sharpest one Sigma 150 f2.8 DG EX macro. Sigma 70mm f2.8 EX DG (special color corrected multi-coating and designed for any format APS or full-frame sensors) is absolutely sharp with great "bokeh" for macro shots and also portraits (sometimes too sharp for portraits).
Summary: I got this lens just in time for a vacation. I ordered it one week before departing and arrived on time. During the vacation it hardly ever left my camera. You can find a very good review of this lens at Photozone (Google photozone sigma 17-70 pentax). Its findings were reflected well in my use. The lens is quite sharp, relatively fast, and improves if stopped down a bit. No glaring weaknesses. The Pentax 17-70 may be a better option for those with newer cameras.
Summary: I decided on the Sigma 17-70 because of the extra speed with the /2.8. While using it at this aperture though, you won't get the sharpest images. It's not so much a dof / focusing issue, but rather a softness which can be noticed when compared to my 50mm prime. Other than that I am over the moon with this purchase. The lens is solid and feels great on the camera. It takes some getting used to when using the reverse zoom action.
Summary: This is currently my favorite lens. Echoing the other reviewers, the range is perfect for a walkaround lens and a perfect sub for the kit lens. Solid construction; it's got some weight to it. Smooth focusing, and sharp images. Macro to boot (see photos I've posted). If you don't have a lens in the 17-70 range or are thinking of upgrading from the kit lens, you should consider investing in this. You'll get your money's worth.