|
Pentamirror
A pentamirror is an optical device used in the viewfinder systems of various single-lens reflex cameras instead of the pentaprism. It is used to reverse again the laterally reversed image coming from the reflex mirror. Instead of the solid block of glass of the prism in pentaprism system, here 3 mirrors are used to perform the same task. This is cheaper and lighter, but generally produces a viewfinder image of lower quality and brightness. This optical device is often (more precisely) referred to as ''roof pentamirror'' because of the roof-like ridge.Paul R. Yoder. ''Opto-Mechanical Systems Design'', 2005page 435 See also *Pentaprism A pentaprism is a five-sided reflecting prism used to deviate a beam of light by a constant 90°, even if the entry beam is not at 90° to the prism. The beam reflects inside the prism ''twice'', allowing the transmission of an image through a r ... * Single-lens reflex camera Notes External linksUnderstanding Viewfinders [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentaprism
A pentaprism is a five-sided reflecting prism used to deviate a beam of light by a constant 90°, even if the entry beam is not at 90° to the prism. The beam reflects inside the prism ''twice'', allowing the transmission of an image through a right angle without inverting it (that is, without changing the image's handedness) as an ordinary right-angle prism or mirror would. The reflections inside the prism are not caused by total internal reflection, since the beams are incident at an angle less than the critical angle (the minimum angle for total internal reflection). Instead, the two faces are coated to provide mirror surfaces. The two opposite transmitting faces are often coated with an antireflection coating to reduce spurious reflections. The fifth face of the prism is not used optically but truncates what would otherwise be an awkward angle joining the two mirrored faces. In cameras A variant of this prism is the roof pentaprism which is commonly used in the viewfinder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentaprism
A pentaprism is a five-sided reflecting prism used to deviate a beam of light by a constant 90°, even if the entry beam is not at 90° to the prism. The beam reflects inside the prism ''twice'', allowing the transmission of an image through a right angle without inverting it (that is, without changing the image's handedness) as an ordinary right-angle prism or mirror would. The reflections inside the prism are not caused by total internal reflection, since the beams are incident at an angle less than the critical angle (the minimum angle for total internal reflection). Instead, the two faces are coated to provide mirror surfaces. The two opposite transmitting faces are often coated with an antireflection coating to reduce spurious reflections. The fifth face of the prism is not used optically but truncates what would otherwise be an awkward angle joining the two mirrored faces. In cameras A variant of this prism is the roof pentaprism which is commonly used in the viewfinder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-lens Reflex
A single-lens reflex camera (SLR) is a camera that typically uses a mirror and prism system (hence "reflex" from the mirror's reflection) that permits the photographer to view through the lens and see exactly what will be captured. With twin lens reflex and rangefinder cameras, the viewed image could be significantly different from the final image. When the shutter button is pressed on most SLRs, the mirror flips out of the light path, allowing light to pass through to the light receptor and the image to be captured. History File:Hasselblad 1600F.jpg, Medium format SLR by Hasselblad (Model 1600F), Sweden File:Zenza BRONICA S2 with ZENZANON 100mm F2.8.JPG, Medium format SLR by Bronica (Model S2), Japan. Bronica's later model—the Bronica EC—was the first medium format SLR camera to use an electrically operated focal-plane shutter File:Asahiflex600.jpg, The 1952 (Pentax) Asahiflex, Japan's first single-lens reflex camera. File:Contaflex BW 2.JPG, The Contaflex III a single- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-lens Reflex Camera
A single-lens reflex camera (SLR) is a camera that typically uses a mirror and prism system (hence "reflex" from the mirror's reflection) that permits the photographer to view through the lens and see exactly what will be captured. With twin lens reflex and rangefinder cameras, the viewed image could be significantly different from the final image. When the shutter button is pressed on most SLRs, the mirror flips out of the light path, allowing light to pass through to the light receptor and the image to be captured. History File:Hasselblad 1600F.jpg, Medium format SLR by Hasselblad (Model 1600F), Sweden File:Zenza BRONICA S2 with ZENZANON 100mm F2.8.JPG, Medium format SLR by Bronica (Model S2), Japan. Bronica's later model—the Bronica EC—was the first medium format SLR camera to use an electrically operated focal-plane shutter File:Asahiflex600.jpg, The 1952 (Pentax) Asahiflex, Japan's first single-lens reflex camera. File:Contaflex BW 2.JPG, The Contaflex III a single- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SLR Pentamirror
SLR may refer to: Science and technology * Satellite laser ranging * Scalable Linear Recording tape drive backup * Sea level rise * Self-loading rifle or semi-automatic rifle ** The UK L1A1 SLR rifle * Semi-linear resolution, a search algorithm * Sending loudness rating for microphones * Simple LR parser (Simple Left-to-right parser) * Single-lens reflex camera ** See also: Digital single-lens reflex camera (digital SLR or DSLR) * SLR (company), a virtual reality company * Service List Registry, of audiovisual services Transport * Holden Torana SLR5000 car * Mercedes-Benz 300 SLR * Mercedes-Benz SLR McLaren * Shimano Linear Response, a bicycle component * Sri Lanka Railways * St. Lawrence and Atlantic Railroad reporting mark Other uses * ''Stanford Law Review'' * Statutory liquidity ratio In India, the Statutory liquidity ratio (SLR) is the Government term for the reserve requirement that commercial banks are required to maintain in the form of cash, gold reserves,Govt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viewfinder
In photography, a viewfinder is what the photographer looks through to compose, and, in many cases, to focus the picture. Most viewfinders are separate, and suffer parallax, while the single-lens reflex camera lets the viewfinder use the main optical system. Viewfinders are used in many cameras of different types: still and movie, film, analog and digital. A zoom camera usually zooms its finder in sync with its lens, one exception being rangefinder cameras. History Before the development of microelectronics and electronic display devices, only optical viewfinders existed. Direct optical viewfinders Direct viewfinders are essentially miniature Galilean telescopes; the viewer's eye was placed at the back, and the scene viewed through the viewfinder optics. A declining minority of point and shoot cameras use them. Parallax error results from the viewfinder being offset from the lens axis, to point above and usually to one side of the lens. The error varies with distance, being ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camera
A camera is an Optics, optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a small hole (the aperture) that allows light to pass through in order to capture an image on a light-sensitive surface (usually a Image sensor, digital sensor or photographic film). Cameras have various mechanisms to control how the light falls onto the light-sensitive surface. Lenses focus the light entering the camera, and the aperture can be narrowed or widened. A Shutter (photography), shutter mechanism determines the amount of time the photosensitive surface is exposed to the light. The still image camera is the main instrument in the art of photography. Captured images may be reproduced later as part of the process of photography, digital imaging, or photographic printing. Similar artistic fields in the moving-image camera dom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mirrors
A mirror or looking glass is an object that Reflection (physics), reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the direction of the image in an equal yet opposite angle from which the light shines upon it. This allows the viewer to see themselves or objects behind them, or even objects that are at an angle from them but out of their field of view, such as around a corner. Natural mirrors have existed since prehistoric times, such as the surface of water, but people have been manufacturing mirrors out of a variety of materials for thousands of years, like stone, metals, and glass. In modern mirrors, metals like silver or aluminium are often used due to their high reflectivity, applied as a thin coating on glass because of its naturally smooth and very Hardness (materials science), hard surface. A mirror is a Wave (physics), wave reflector. Light consis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
