ABSTRACT
Photographic lenses and associated optics are commonplace examples of very advanced technology. A number of valid optical requirements may be identified for photography which may differ from those of other optical systems, e.g. as for astronomy. A significant difference in optical terms is the unusually large acceptance angle of a photographic lens, usually called the field of view or angle of view, as compared with, say, telescopes, microscopes or spectroscopes. Complex optical means have been devised to approximate to this requirement, particularly so in wide-angle lenses. Use of an additional range of optical materials and crystals permits imaging in spectral bands outside the visible region. While the prime imaging lens of a camera naturally receives most attention, ancillary optical systems of some complexity, especially for viewfinding or focusing purposes, also have to meet severe requirements for their imaging capabilities and have extended interfacing with integral opto-electronic or electro-optical devices to extend their functions.
