Sigma DC 17-70mm F 2.8-4 Macro OS HSM

Perfect walk around, low light and portrait zoom lens for aps-c cameras The version I got is the Sigma 17-70 F/2.8-4 DC Macro HSM. It is not the OS (Optical Stabilzer) model. This particular version is in the Pentax K mount so OS was not needed anyways. Since vetting the lens, I've put it through the ringer. Shot Portraits both with off camera flash and natural light wide open. Low light portraits wide open. Each situation resulted in near prime lens sharpness. Astrophotography was a bit difficult because the lens can focus past infinity and the throw isn't very long, so making micro adjustments is pretty hard to pull off. The flip side is this, once It's dialed in, the contrast, saturation and color are amazing! The details really stand out. I was told by a number of my pro photog friends to grab the 17-50 2.8 since it's a fixed aperture. I decided not to since if I want a shallow depth of field I can use the compression of the extra 20 mm in focal length for pretty much the same effect at F/4 as I would get with 50 mm at 2.8. Not to mention the extreme close focusing that the 17-70 allows is awesome! It's not true 1:1 macro but with the proper post processing technique you can easily create 1:1 macros with this lens without loss of quality. I highly recommend this lens if you're looking for a high quality lens for travel, walk around, landscapes and portraits and/or you'd like an upgrade from the kit lens. Just keep in mind that the Sigma isn't weather sealed.

good lens for the price the lens is hefty for its size. well-made, good fit and details. the lens takes good pictures, and the zoom range is very handy. the one drawback is that the lens does not let in enough light. i expected to be able to take pictures in lower light situations, but the lens struggles in this area. I realize that f2.8 is not a huge aperature, but i expected a bit more. in mid to bright light situations, this lens rocks! i took pictures of the high school track meet, and all but the fastest feet and hands were well in focus and not blurred. overall a good buy, and fairly versatile, except for low light.

Light Weight and Sharp Enough! A great alternative for crop sensors at an affordable price. Not tack sharp wide open but step down to 4.0 at the lower end and 5.6 at the high end and it is perfect. Bokeh is very good but not perfect. For the price you pay I think is is a great lens. For Macro, please buy a dedicated macro lens instead.