Sigma 70-300mm f/4-5.6 DG OS Zoom Lens Review by ePhotoZine With Rating 6/10

The OS function offers the use of shutter speeds approximately 4 stops of hand-holdability. It makes telephoto shooting easy for many types of photography such as sport and nature. For Sony and Pentax mount, the built-in OS function of this lens can be used even if the camera body is equipped with an anti-shake function. The lens is currently selling at around $399.99 and here is the summary of the latest review of the lens by ePhotoZine, giving the lens a rating of 6 out of 10

"At 70mm this lens produces images of good resolution from the widest aperture right down to f/16, with the edges gradually improving as the lens is stopped down. The best quality images at 70mm are produced between f/8 and f/11. By 135mm, there has been a slight drop in resolution, with the lens still producing good centre sharpness wide open. The best quality images are still produced between f/8 and f/11 with the sharpness across the frame being absolutely uniform at f/11. Venture further into the zoom range and the clarity drops off noticeably. The lens is still capable of producing acceptable results for most wide open, but stopping down a couple of stops will improve the clarity of images. In use, I did notice a drop in contrast at 300mm, which will affect the apparent sharpness of images.

Sigma's Optical Stabilisation system helps greatly with being able to take images in low light conditions and at slower shutter speeds. I was able to take sharp hand-held shots most of the time at shutter speeds of 1/15sec at 70mm and 1/30sec at 300mm, which is pretty good performance and will help greatly to tame camera shake. Overall. the Sigma 70-300mm OS is a good value alternative to the camera manufacturer's own offerings, providing decent enough resolution at a lower price point than independent equivalents with low distortion and decent enough resistance to flare and ghosting. Although the resolution tails off at the longer end of the lens, the clarity produced will still satisfy all but the most demanding photographers."