I'm having a hard time finding Alpha A-mount lenses for my Sony SLT A55 camera. Sony is now moving towards mirrorless cameras, which are thinner and use a different E-mount lens but still use the Alpha designation. This is an excellent mid-telephoto zoom lens. I found it to focus quickly, be very sharp and have minimal chromatic distortion. It uses the same 55mm filter as my other lenses. The lens is lightweight yet durable. I personally didn't find it "plastic" like others have said. This only applies to cameras with an APS-C sensor, vignetting will occur on a full-frame camera. Good price for a quality lens. Excellent bokeh (blurred blur) The only drawback is that the front element rotates when focusing. I can't use polarized or split density filters. Full frame equivalent 80-300mm Suitable for sports, wildlife and portrait photography.