The Carl Zeiss compact T* 500mm Mirotar f8 catadioptric lens. The Mirotar is less than five inches long and three and one half inches in diameter. It is composed of six elements in four groups, two are extremely high quality mirrors.
The system used in Carl Zeiss Mirotar lenses to reduce the size is called folded optics. It consists of the primary mirror re-directing light forward to the inside of the center spot at the front of the lens. This light is then re-directed by a smaller mirror back to the rear of the lens where it passes though a hole in the center of the primary mirror. The light is then further corrected by achromatized refractive lens elements before exiting the lens and passing to the film.
S p e c i f i c a t i o n s:
Number of Elements: 6
Number of Groups: 4
Max. Aperture: f/8
Focal Length: 500mm
Negative Size: 24 x 26mm
Angular Field: 2 w 4.9ø diagonal
Mount: Contax/Yashica bayonet mount
Aperture Scale: 8 (Fixed)
Filter Connection: 82mm screw-in type
Weight approx: 795g
Distance Range: to 3.5m (11.5 ft)