Unlike other adapters, the Elite adapter does not use a light-robbing eyepiece to project the image from the scope to the film plane. Instead, it uses a multi-lens no-eyepiece optical system for sharp, flat-field images similar in quality to those produced by telephoto lenses designed strictly for camera use. All air-to-glass surfaces in the adapter are fully multicoated for high light transmission and contrast. Plastic endcaps keep dust out of the optical system when the adapter is not in use. A thumbscrew in the side of adapter allows you to change the camera orientation from portrait to landscape in a matter of seconds.