This describes the item's appearance under normal lighting conditions. Please refrain from purchasing if you are seeking perfection. Please consider the above information before making a purchase. The mount is a T-mount. The minimum focusing distance is 1.72m. It is a T-mount 42mm screw mount. The thread pitch is different from the M42 mount, so a separate T-mount adapter is required. Mirror lenses do not have aperture blades, so light adjustment is done with ND filters, etc. You can enjoy the ring bokeh unique to mirror lenses. Although it is f/8, it is a 500mm telephoto lens, so it feels quite bright outdoors during the day. Operation is not a problem. The focusing ring moves smoothly. The coating is also in good condition. Yes Thank you for viewing.