The Sakar 2146W lens is a lens converter.�When photographers�use this lens in conjunction with their current lens, it makes the current lens a wide-angle lens. Wide-angle lenses generally have very small focal lengths. As the name suggests, a wide-angle lens will allow the user to capture a wider view of the scene in his or her photograph. In general, when using a lens converter, the user must remove the original lens, attach the converter to the camera, and attach the original lens to the converter. The Sakar 2146W lens has a 46-mm focal length, and it is a 0.42x lens. It features crystal optics, and it is an ultra wide-angle macro lens. The lens itself is multi-coated, and can be used with autofocus cameras and lenses. The Sakar 2146W lens features a 67-mm filter thread, and in some cases users will need to buy filter adapters to attach this product to their camera.