Prominar super-telephoto lenses incorporate fluorite crystal lenses to realize a high resolution
In order to limit chromatic aberration (color blur) to the utmost, which tends to easily occur in lenses with long focal lengths, one fluorite crystal lens and two XD (eXtra lod Dispersion) lenses having particularly low dispersion capabilities are utilized. By bringing together advanced optical technology fostered through the development of spotting scopes, and incorporating fluorite crystal lenses with outstanding optical characteristics, high contrast and extremely sharp images can also be realized as a camera lens. Further, due to the high-level aberration correction and the utilization of a rounded diaphragm, an attractive effect can be obtained in out-of-focus areas as the pinnacle of imaging expression for a camera lens.

Dual-focus system that realizes ease of use in manual focusing
To enable the focus to be precisely adjusted by manual focusing. Kowa spotting scopes also utilize a highly reputed dual-focus system. In addition to using a high-contrast optical system that enables the focusing peak to be easily determined, a dual-focus system consisting of a quick focus that swiftly matches the focus and a fine focus for delicate focus adjustment is used. This enables precise adjustment to be carried out, even under the severe conditions encountered in super-telephotography.

Three types of focal lengths, 350mm, 500mm and 850mm can be used as required in the one unit
From the standard specifications of 500mm F5.6, it is possible to change the focal length of the master lens to a brighter 350mm F4 super-telephoto lens using the TX07 optional mount adapter, ot to a lens with an even higher super-telephoto effect of 850mm F9.6 using the optional mount adapter TX17. The 350mm and 850mm mount adapters have been designed specifically for use in combination with the master lens, and the incorporation of XD lenses also inside each of the mount adapters realizes an outstanding optical performance comparable to that of previous dedicated lenses. (All lenses support 35mm full size format).

Mount interchanging system that allows effective use of cameras made by several manufacturers
Anticipating the use of digital cameras made by several different manufacturers, a bayonet mount system is utilized that allows easy mounting and release. This makes it possible not only to exchange each of the mount adapters in an instant. Since the prism unit also employs an exchanging system that utilizes bayonet mounting, the switching between photographing and viewing can also be easily carried out. (Supported mounts: Nikon mount, Canon mount, Pentax mount, Micro Four Thirds mount, Sony "A" mount).

A new-concept lens having two "faces" that increase the scope of use as a high performance spotting scope
By connecting the optional prism unit and eyepiece, the telephoto lens can be used as a spotting scope by effectively making use of the high performance master lens optical system. Due to the utilization of a mounting and release system that uses a bayonet mount, the single telephoto lens can be easily used both for "photographing" and "viewing". Clear images can be enjoyed with a feeling of transparency since there is no focusing screen.

Digiscoping opens up a world of even higher super-telephotography between 1000mm and 3000mm*
By connecting an optional digital camera adapter to the lens in the spotting scope condition, it will be possible to carry out digiscoping using a compact digital camera.
Using digiscoping, it will be possible to carry out even higher super-telephotography between approximately 1000mm and 3000mm*, allowing wild birds and other subjects to be photographed at long ranges that would not be possible using digital SLR cameras. (Eyepieces that support digiscoping: TE-17W, TE-10Z, and TE-20H) *35mm format equivalent effective focal length.

Lightweight and compact design that realizes outstanding portability
The 500mm super-telephoto lens only weighs around 67 oz. The portability is extremely good, and the lightweight design also allows hand-held shooting. Further, when the mount adapter is removed, the compact design with a total length of only approximately 9.84 inches allows it to be carried in a small rucksack.

Tripod mounting foot that allows mounting on video heads without modification
The tripod mounting foot has a format that allows mounting on some types of Manfrotto and Gitzo video heads without requiring a quick shoe. Simple mounting and release is possible on the video heads mentioned above, so that the lens can be used without worrying about the tripod screw coming loose. Mounting can also be carried out on other manufacturers' tripod heads. (1/4 inch screws are supported).

Lens hood with attached sighting device allows objects to be captured quickly
A lightweight lens hood is provided as a standard accessory.
In order to increase the speed for introducing the subject into the field of view when carrying out super-telephotography, a sighting function is incorporated in the hood. The hood mounting screw has a special shape that assists with the swift sighting of objects when used in combination with the included sighting devices.

Dustproof and Weatherproof Structure
The objective lens and focusing units utilize rubber O-rings to seal the housing of the lens for enhanced dust and weatherproofing.