The 15x50IS AW is unique among high-magnification binoculars because they incorporate Canon remarkable Optical Image Stabilizer technology. Proven highly effective in Canon video camcorders and professional lenses, this revolutionary system employs a novel Vari- Angle Prism that instantly and continuously makes adjustments to maintain a steady image. With Canon Optical Image Stabilizer, you can enjoy the resolving power of these binoculars without a tripod. You can even use them from within moving vehicles. Their shake-free performance not only enhances your ability to view fine detail but also reduces eye strain and fatigue. The IS series feature eyepiece lenses with a unique Doublet Field Flattener, which dramatically reduces curvature of field. As a result, there is none of the image distortion and blurring at the periphery typical of high-magnification binoculars. This advanced design also results in long eye relief, which enables eyeglass wearers to view the entire field without vignetting. Canon superior optical engineering also provides unusually wide apparent field-of view. This is particularly important in high magnification binoculars as it makes it easier to locate your desired subject.