Kit comprising lens + T-mount adapter for Nikon F mount
Compact Telephoto Lens
A focal length of 500 mm in a lens just under 9 cm long will make any camera with this lens into a secret telephoto champion. The long focal length in such a short lens is achieved by using mirrors in the beam path, a technology that has long been used in telescopes.
The light entering the lens hits a ring-shaped parabolic mirror and is reflected back towards the lens opening, where it meets a secondary mirror. From there it is reflected back and through the middle of the initial parabolic mirror, on through lenses and finally onto the camera sensor. Basically, this is the same technology as in the Hubble Space Telescope.
Constant aperture of f/8.0
By design, an iris mechanism is not fitted in the lens. The constant aperture is f/8.0. Stopping down is achieved by screwing one of the three included filters (one skylight, two ND) between the lens and the camera. There always needs to be one of those filters mounted to provide the necessary flange focal distance. Exposure is regulated by choosing a filter and by exposure time.
Very low chromatic aberration, unique bokeh
A big advantage of this type of construction is the extremely low chromatic aberration. In the Bokeh, points of lights always produce small rings – your images will definitely be unmistakable. The lens is also well suited for photography of the moon, and with protective sun filter foil also for the sun.
Connectivity for most cameras by T-mount
The lens comes with a T-mount plus a Nikon F mount adapter for your camera. With other adapters, you can use the lens on most cameras with interchangeable lenses. The focal length changes according to the crop factor of the respective camera. The focus is controlled manually.