Samyang 500mm MC IF f/6.3 Mirror Lens.
The Samyang 500 mm MC IF f/6.3 Mirror is a manual focus fixed aperture reflex design compact telephoto lens, primarily designed for amateur and enthusiasts on a tight budget.
This f/6.3 fixed aperture version features improved light gathering ability over the f8 version, and is larger in size. However it is still compact and lightweight for a 500mm lens.
The Samyang 500mm MC IF f/6.3 is suitable for photographing nature, astrophotography, spy / observational photography or any situation where a low priced, relatively lightweight long telephoto is desired.