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Konica Hexar
The Konica Hexar is a 35 mm fixed-lens, fixed focal length autofocus camera which was produced through the 1990s. It was introduced to the market in 1993. While styled like a rangefinder camera, and intended for a similar style of photography, in specification it is more like a larger "point and shoot" camera. The Konica Hexar enjoys something of a "cult status" among film camera aficionados because of the quality of its lens, rangefinder-style ergonomics and interesting and useful operating modes (notably its "silent mode"). Lens The camera is fitted with a 35mm fixed- focal length lens with autofocus and with a large maximum aperture of f2. The lens accepts lens filters of 46mm diameter (however, camera settings must be manually adjusted to compensate for any reduction in light transmission caused by the filter). A metal pull-out lens hood surrounds the lens. The lens on the Hexar is considered to be of high quality for this type of camera and is often compared with oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
135 Film
135 film, more popularly referred to as 35 mm film or 35 mm, is a format of photographic film used for still photography. It is a film with a film gauge of loaded into a standardized type of magazine – also referred to as a cassette or cartridge – for use in 135 film cameras. The engineering standard for this film is controlled by ISO 1007 titled '135-size film and magazine'. The term 135 was introduced by Kodak in 1934 as a designation for 35 mm film specifically for still photography, perforated with Kodak Standard perforations. It quickly grew in popularity, surpassing 120 film by the late 1960s to become the most popular photographic film size. Despite competition from formats such as 828, 126, 110, and APS, it remains the most popular film size today. The size of the 135 film frame with its aspect ratio of 1:1.50 has been adopted by many high-end digital single-lens reflex and digital mirrorless cameras, commonly referred to as " full frame". Eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leica M Mount
The Leica M mount is a camera lens mount introduced in 1954 with the Leica M3, and a range of lenses. It has been used on all the Leica M-series cameras and certain accessories (e.g. Visoflex reflex viewing attachment) up to the current film Leica M-A and digital Leica M11 cameras. This lens mount has also been used by Epson, Ricoh, Minolta, Konica, Cosina Voigtländer, Rollei, Carl Zeiss AG and Rollei Fototechnic on some of their cameras. Overview The Leica M mount was introduced in 1954 at that year's Photokina show, with the Leica M3 as its first camera. The 'M' stands for ''Messsucher'' or rangefinder in German. This new camera abandoned the M39 lens mount in favour of a new bayonet mount. The bayonet mount allowed lenses to be changed more quickly and made the fitting more secure. Other innovations introduced by the M3 included a single window for the viewfinder (for composition) and the rangefinder (for focussing). With a double-stroke film advance lever (later models ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exposure (photography)
In photography, exposure is the amount of light per unit area (the image plane's illuminance times the exposure time) reaching a frame of photographic film or the surface of an electronic image sensor, as determined by shutter speed, lens F-number, and scene luminance. Exposure is measured in lux seconds, and can be computed from exposure value (EV) and scene luminance in a specified region. An "exposure" is a single shutter cycle. For example, a long exposure refers to a single, long shutter cycle to gather enough dim light, whereas a multiple exposure involves a series of shutter cycles, effectively layering a series of photographs in one image. The accumulated ''photometric exposure'' (''H''v) is the same so long as the total exposure time is the same. Definitions Radiant exposure Radiant exposure of a ''surface'', denoted ''H''e ("e" for "energetic", to avoid confusion with photometric quantities) and measured in , is given by :H_\mathrm = E_\mathrmt, where *''E'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around 1 millimeter (300 GHz) to the nominal red edge of the visible spectrum, around 700 nanometers (430 THz). Longer IR wavelengths (30 μm-100 μm) are sometimes included as part of the terahertz radiation range. Almost all black-body radiation from objects near room temperature is at infrared wavelengths. As a form of electromagnetic radiation, IR propagates energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon. It was long known that fires emit invisible heat; in 1681 the pioneering experimenter Edme Mariotte showed that glass, though transparent to sunlight, obstructed radiant heat. In 1800 the astronomer Sir William Herschel discovered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battery (electricity)
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell. Primary (single-use or "disposable") batteries are used once and discarded, as the electrode materials are irreversibly changed during discharge; a common example is the alkaline battery used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stepper Motor
A stepper motor, also known as step motor or stepping motor, is a brushless DC electric motor that divides a full rotation into a number of equal steps. The motor's position can be commanded to move and hold at one of these steps without any position sensor for feedback (an open-loop controller), as long as the motor is correctly sized to the application in respect to torque and speed. Switched reluctance motors are very large stepping motors with a reduced pole count, and generally are closed-loop commutated. Mechanism Brushed DC motors rotate continuously when DC voltage is applied to their terminals. The stepper motor is known for its property of converting a train of input pulses (typically square waves) into a precisely defined increment in the shaft’s rotational position. Each pulse rotates the shaft through a fixed angle. Stepper motors effectively have multiple "toothed" electromagnets arranged as a stator around a central rotor, a gear-shaped piece of iron. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetism
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of atoms and molecules. Electromagnetism can be thought of as a combination of electricity and magnetism, two distinct but closely intertwined phenomena. In essence, electric forces occur between any two charged particles, causing an attraction between particles with opposite charges and repulsion between particles with the same charge, while magnetism is an interaction that occurs exclusively between ''moving'' charged particles. These two effects combine to create electromagnetic fields in the vicinity of charge particles, which can exert influence on other particles via the Lorentz force. At high energy, the weak force and electromagnetic force are unified as a single electroweak force. The electromagnetic force is responsible for many o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Firmware
In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide hardware abstraction services to higher-level software such as operating systems. For less complex devices, firmware may act as the device's complete operating system, performing all control, monitoring and data manipulation functions. Typical examples of devices containing firmware are embedded systems (running embedded software), home and personal-use appliances, computers, and computer peripherals. Firmware is held in non-volatile memory devices such as ROM, EPROM, EEPROM, and flash memory. Updating firmware requires ROM integrated circuits to be physically replaced, or EPROM or flash memory to be reprogrammed through a special procedure. Some firmware memory devices are permanently installed and cannot be changed after manufacture. C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mail, telephony, and file sharing. The origins of the Internet date back to the development of packet switching and research commissioned by the United States Department of Defense in the 1960s to enable time-sharing of computers. The primary precursor network, the ARPANET, initially served as a backbone for interconnection of regional academic and military networks in the 1970s to enable resource shari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intellectual Property
Intellectual property (IP) is a category of property that includes intangible creations of the human intellect. There are many types of intellectual property, and some countries recognize more than others. The best-known types are patents, copyrights, trademarks, and trade secrets. The modern concept of intellectual property developed in England in the 17th and 18th centuries. The term "intellectual property" began to be used in the 19th century, though it was not until the late 20th century that intellectual property became commonplace in the majority of the world's legal systems."property as a common descriptor of the field probably traces to the foundation of the World Intellectual Property Organization (WIPO) by the United Nations." in Mark A. Lemley''Property, Intellectual Property, and Free Riding'', Texas Law Review, 2005, Vol. 83:1031, page 1033, footnote 4. The main purpose of intellectual property law is to encourage the creation of a wide variety of intellectual goo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shutter (photography)
In photography, a shutter is a device that allows light to pass for a determined period, exposing photographic film or a photosensitive digital sensor to light in order to capture a permanent image of a scene. A shutter can also be used to allow pulses of light to pass outwards, as seen in a movie projector or a signal lamp. A shutter of variable speed is used to control exposure time of the film. The shutter is constructed so that it automatically closes after a certain required time interval. The speed of the shutter is controlled by a ring outside the camera, on which various timings are marked. Camera shutter Camera shutters can be fitted in several positions: * Leaf shutters are usually fitted within a lens assembly (''central shutter''), or more rarely immediately behind (''behind-the-lens shutter'') or, even more rarely, in front of a lens, and shut off the beam of light where it is narrow. *Focal-plane shutters are mounted near the focal plane and move to uncover the fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1987
File:1987 Events Collage.png, From top left, clockwise: The MS Herald of Free Enterprise capsizes after leaving the Port of Zeebrugge in Belgium, killing 193; Northwest Airlines Flight 255 crashes after takeoff from Detroit Metropolitan Airport, killing everyone except a little girl; The King's Cross fire kills 31 people after a fire under an escalator flashes-over; The MV Doña Paz sinks after colliding with an oil tanker, drowning almost 4,400 passengers and crew; Typhoon Nina strikes the Philippines; LOT Polish Airlines Flight 5055 crashes outside of Warsaw, taking the lives of all aboard; The USS Stark is struck by Iraqi Exocet missiles in the Persian Gulf; U.S. President Ronald Reagan gives a famous speech, demanding that Soviet leader Mikhail Gorbachev tears down the Berlin Wall., 300x300px, thumb rect 0 0 200 200 Zeebrugge disaster rect 200 0 400 200 Northwest Airlines Flight 255 rect 400 0 600 200 King's Cross fire rect 0 200 300 400 Tear down this wall! rect 300 200 6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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