The lens I now have a month and I have to say it makes really good pictures, with my Samsung GX20. It is also relatively small and light. I have 4 stars because, because the lens could not tolerate a few improvements. - About the OS (Optical Stabilizer) function You should allow up to 4 stops slower shutter speed according to brochure, I find something high. Although my GX20 also has a stabilizer, but not working as well as of the Sigma lens 17 -50 Even the one point in the brochure - Make sure that the OS switch is OFF before you begin your lens to the camera or remove it from the camera. That I will certainly often forgotten - and what happens then.
- Setting the Focus and Focal Length Another Sigma atypical point loud brochure - To avoid damage to the AF mechanism may the focusing ring does not rotate by hand, as long as the Receiving unit is set to autofocus. Sounds logical. But I also have a Sigma 50-150 HSM which do not mind. It can happen that you come to the focus ring but always.
From the pictures here I have made so far, the lens 17 is - 50 2.8 Top.
