Afocal photography

[1] Afocal photography works with any system that can produce a virtual image of parallel light, for example telescopes and microscopes.

[3] The advent of digital single-lens reflex camera and, moreover, compact point and shoot digital cameras has made the afocal method far more popular since this type of camera is small enough to mount directly on to telescopes or other devices, is for the most part a solid state device with minimal moving parts, has auto focus, has auto exposure adjustment, has some capacity for time exposure, usually has a zoom mechanism to crop vignetting, and has a digital viewframe that allows the user to see the image hitting the viewing plane.

[4] Almost from their invention amateur astronomers were adapting compact digital still and video cameras for use in afocal astrophotography.

[5] But since most celestial objects require a long exposure, compact consumer digital cameras are somewhat problematic due to their high inherent sensor noise.

Since the development of compact digital cameras, afocal photography is also widely used by birdwatchers, naturalists, and other photographers.

It also facilitates the use of a very long lens without buying and transporting extra equipment, other than perhaps a small afocal adapter.