Search results
Results from the WOW.Com Content Network
Early pinhole camera. Light enters a dark box through a small hole and creates an inverted image on the wall opposite the hole. [8]The first known description of pinhole photography is found in the 1856 book The Stereoscope by Scottish inventor David Brewster, including the description of the idea as "a camera without lenses, and with only a pin-hole".
The lightmeter is activated by a lever on the side of the camera, which also stopped down the lens. A Mercury battery (1.35 V Mallory RM640) was used to power the light metering system; however due to the way the circuit is designed, 1.5 V silver oxide batteries can be used instead.
A twin-lens reflex camera (TLR) is a type of camera with two objective lenses of the same focal length. One of the lenses is the photographic objective or "taking lens" (the lens that takes the picture), while the other is used for the viewfinder system, [1] which is usually viewed from above at waist level.
An improvised pinhole has a similar but better effect. The same principle has also been applied as an alternative to corrective lenses: a screen of pinholes is mounted on an eyeglass frame and worn as pinhole glasses. Differential diagnosis: pinhole worsen vision: Macular diseases, [5] central lens opacities [6] Vision static with pinhole ...
A small pinhole can act as a lens, focusing light. This effect is used in pinhole cameras and camera obscura , and in solarigraphy . This effect is also used in pinhole occluders , which are used by ophthalmologists , orthoptists , and optometrists to test visual acuity .
The M42 lens mount is a screw thread mounting standard for attaching lenses to 35 mm cameras, primarily single-lens reflex models. It is more accurately known as the M42 × 1 mm standard, which means that it is a metric screw thread of 42 mm diameter and 1 mm thread pitch.
Lenses that support it include those labelled 'SMC Pentax', 'SMC Pentax-M' and 'SMC Pentax-A'. These K-mount bodies cannot use lenses that lack an aperture ring, such as FAJ or DA. K-mount lenses can be used on all Pentax bodies, but are restricted to stopped down mode when used with "crippled" K AF-mount bodies (see below).
Different kinds of camera lenses, including wide angle, telephoto and speciality. A camera lens (also known as photographic lens or photographic objective) is an optical lens or assembly of lenses (compound lens) used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.