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The first mass-produced autofocus camera was the Konica C35 AF, a simple point and shoot model released in 1977. The Polaroid SX-70 Sonar OneStep was the first autofocus single-lens reflex camera, released in 1978. The Pentax ME-F, which used focus sensors in the camera body coupled with a motorized lens, became the first autofocus 35 mm SLR in ...
The lensmeter is also used to check the accuracy of progressive lenses, and is often capable of marking the lens center and various other measurements critical to proper performance of the lens. It may also be used prior to an eye examination to obtain the last prescription the patient was given, in order to expedite the subsequent examination.
The f-number N is given by: = where f is the focal length, and D is the diameter of the entrance pupil (effective aperture).It is customary to write f-numbers preceded by "f /", which forms a mathematical expression of the entrance pupil's diameter in terms of f and N. [1]
This shaft driven autofocus design has several benefits such as allowing for smaller and lighter lenses and also keeps the cost of lenses down because there are no internal focusing motors or digital interfaces built into the lens. Keeping the autofocus motors inside the camera body and as far away from the lens glass as possible, reduces ...
Although the ME F was an interchangeable lens camera (the photographer could remove and exchange its lens for another), its AF function required the unique SMC Pentax AF 35 mm–70 mm f/2.8 Zoom Lens autofocus lens using a special Pentax K-F lens mount. Unlike all later Pentax AF SLRs, the ME F did not have the focusing drive motor and keying ...
Varifocal lenses are also used in many modern autofocus cameras as the lenses are cheaper and simpler to construct and the autofocus can take care of the re-focussing requirements. Many modern zoom lenses are now confocal, meaning that the focus is maintained throughout the zoom range. Because of the need to operate over a range of focal ...
A telecentric lens is a special optical lens (often an objective lens or a camera lens) that has its entrance or exit pupil, or both, at infinity. The size of images produced by a telecentric lens is insensitive to either the distance between an object being imaged and the lens, or the distance between the image plane and the lens, or both, and ...
Diagram illustrating the flange focal length of an SLR–type and a mirrorless–type camera. For an interchangeable lens camera, the flange focal distance (FFD) (also known as the flange-to-film distance, flange focal depth, flange back distance (FBD), flange focal length (FFL), back focus [1] or register, depending on the usage and source) of a lens mount system is the distance from the ...