"The Kenko Lens2Scope Adapter for Canon EF Mount Straight Finder is an accessory that can change any lens into a spotting scope. The Lens2Scope adapter's light-weight composite body houses a high quality roof prism, optics and an eyepiece just like a traditional spotting scope. When the lens is attached, it becomes a spotting scope to use for viewing. The lens mount and housing for the optics are made from metal while some external barrels are polycarbonate.The optics in the Lens2Scope magnify the image by a factor of 10x so that a 100mm lens would have the same magnification as a 1,000mm lens when viewing. Focus is easily achieved by using the lens' manual focus ring.The Lens2Scope has a removable tripod adapter for mounting onto a tripod for more comfortable viewing for extended periods of time.This small accessory comes with its own carrying case and takes up about as much room in a camera bag as a normal lens."