Within the classification of the lenses used for photography and video, there are those who by their long focal length (physical or emulated) have the ability to magnify objects. These objectives are referred to as telephoto. The telephotos are also divided into several classes in structure and can be fixed or variable focal length (zoom).
In the construction of fixed telephoto two approaches are used
The catadioptric objectives are built under a technology that combines two fundamental physical principles of optics: refraction and reflection.
This approach has several advantages
In contrast, the disadvantages that such goals are present
The catadioptric technology is not used exclusively for visual recording cameras, also used in systems similar approach as search lights (strip aircraft), concentrating reflectors, headlights, telescopes and microscopes.
Also known as: Objective lens or mirror.
Spelling: Objective CAT
Common spelling errors: Objective catadrioptic