Vivitar Series 1 800mm f11 VMC Solid Catadioptric Lens for Nikon F brand_Pentax most notably on the rivets

most notably on the rivets

5cm images on standard 120 rollfilm

according to Mannheim's "The Rollei Way"

The Nikon MB-D15 is a vertical grip and battery holder for the Nikon D7100

Essentially

Vivitar Series 1 800mm f11 VMC Solid Catadioptric Lens for Nikon F brand_Pentax most notably on the rivetsAn 800mm lens that's less that 10cm long? Yes please. To be fair, it's also 10cm across and weighs 1. 5kg, but that's still pretty darn impressive. Smooth focusing, clean optics, remarkably good imaging (with the usual out of focus donut shapes, of course.) An unusual lens in excellent condition. This is a T mount lens, compatible with most film and digital camera systems; it includes a Nikon F mount.