 The image stabilizer is rated for 4 stops and allows sharp pictures to be taken handheld at speeds as slow as 1/8 of a second.This lens has superb contrast that meets or exceeds other L-series telephoto zooms, but lacks in sharpness in the corners throughout most of its focal length range.The image quality at 300mm does not degrade, making it distinct from the other 70–300mm lenses.