" L " Glass Quality At A Cheap Price, Low Weight. Great Outdoor All Around Lens. ( No , not a good indoor lens like a 70-200mm F2.8 IS,, but for half the weight and half the price. A very good lens, esp. if you use a cropped sensor 20D,30D, 40 D or one of the many verison's of Rebels.. (Attached Here To My 5D,, the " Poor Boy's Pro Camera )