A constant aperture F2.8, focal range starting at 16mm, a "pro" finish, a silent ssm engine, fast and accurate, it is the objective to possess with the latest Sony alpha (A77, A65) which the sensor is demanding. Compared with the kit zoom (18-55) is another world for a price that may be able to look elevé to some but which is actually a bargain (the cheapest transtandard constant aperture F2. 8 labels). Total satisfaction for me and a big thank you to Sony.