Camera

• 1. Introduction

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  A camera is an instrument for capturing and storing images and videos, either digitally through an electronic image sensor or chemically through a light-sensitive material like photographic film. That single definition hides a long and restless history. The invention of the camera dates back to the 19th century, and it has been changing ever since. By the 21st century, that one idea had split into a vast array of types and models, each shaped for a different job. There is a question buried in all of this. How does an enclosed box with a lens become something that influences how an entire society creates, shares, and consumes visual content? And what happened when the camera stopped being a dedicated device and slipped inside the phone in your pocket? To understand any of it, you have to understand light, and what a camera does to it.

• 2. Anatomy Of Light

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  Light enters an enclosed box through a converging or convex lens, and an image is recorded on a light-sensitive medium. That is the basic design shared by all cameras. A shutter mechanism controls the length of time that light enters the camera. Most cameras also carry a viewfinder, which shows the scene to be recorded, plus controls to adjust focus, aperture, and shutter speed. Most cameras capture light from the visible light spectrum. Specialized cameras reach into other portions of the electromagnetic spectrum, such as infrared. Exposure control is the heart of the system, and it works through two cooperating mechanisms. The aperture is an opening adjusted by overlapping plates called the aperture ring, usually located in the lens. As it is adjusted, the opening expands and contracts in increments called f-stops. The light entering the camera is halved with each increasing increment, and standard f-stops range from 1.4 to 32. A wider opening at lower f-stops narrows the range of focus, so the background blurs while the foreground stays sharp. The shutter is the second control. It determines the duration that the light-sensitive surface is exposed. Typical exposure times can range from one second to one thousandth of a second. In the early stages of photography, exposures were often several minutes long, which produced blurry images. There is a direct relationship between the two settings. Lengthen the exposure time one step, narrow the aperture one step, and the amount of light reaching the film or sensor stays the same. That balance is what a built-in light meter helps the camera solve before a single frame is taken.

• 3. The Glass That Sees

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  A camera lens is an assembly of multiple optical elements, typically made from high-quality glass, whose job is to focus light onto the film or digital sensor. Each element is designed to reduce optical aberrations, the distortions that degrade an image. Chromatic aberration is a failure of the lens to focus all colors at the same point. Vignetting is the darkening of image corners. Distortion is the bending or warping of the image. The focal length of the lens, measured in millimeters, decides how much of the scene the camera captures and how large objects appear. Wide-angle lenses provide a broad view of the scene, while telephoto lenses capture a narrower view but magnify the objects. Longer focal lengths also make it harder to avoid blur from small camera movements when shooting handheld. Two primary types divide the field. A zoom lens allows for changing its focal length within a certain range. A prime lens has a fixed focal length, and while less flexible, prime lenses often provide superior image quality, tend to be lighter, and perform better in low light. Focus is adjusted through the focus ring, which moves the lens elements closer to or farther from the sensor. Autofocus uses a motor within the lens to adjust focus based on contrast or phase differences. Advanced lenses may include mechanical image stabilization that moves lens elements or the sensor itself to counteract camera shake. All of that glass exists to deliver light to whatever sits at the back of the box, and that surface has taken two very different forms.

• 4. Film Versus Sensor

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  Loading film into a film camera is a manual process. The film, typically housed in a cartridge, is loaded into a designated slot, and one end of the strip, the film leader, is threaded onto a take-up spool. The film must be advanced after each shot to prevent double exposure, where the same section of film is exposed to light twice, producing overlapped images. Once every frame on the roll has been exposed, the film is rewound back into the cartridge, ready to be removed for developing. A digital sensor works on an entirely different principle. Sensors typically comprise Charge-Coupled Devices, known as CCDs, or Complementary Metal-Oxide-Semiconductor chips, known as CMOS, both of which convert incoming light into electrical charges to form digital images. CCD sensors, though power-intensive, are recognized for excellent light sensitivity and image quality. CMOS sensors offer individual pixel readouts, which leads to less power consumption and faster frame rates. Digital cameras convert light into electronic data that can be directly processed and stored, with the volume of data dictated by the sensor's size and properties. That data needs somewhere to live, which is why storage media such as Compact Flash, Memory Sticks, and SD cards became part of the kit. The advantage over film is flexibility. Digital images are more readily handled and manipulated by computers, offering real post-processing potential. The first camera to use digital electronics to capture and store images was built by Kodak engineer Steven Sasson in 1975, using a CCD from Fairchild Semiconductor that provided only 0.01 megapixels and saved black and white images onto a cassette tape.

• 5. A Family Of Forms

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  The Asahiflex II, released by the Japanese company Asahi, also known as Pentax, in 1954, was the world's first SLR camera with an instant return mirror. That detail captures what makes the single-lens reflex camera distinctive. A mirror redirects light from the lens to the viewfinder for composing and focusing. When the shutter is released, the mirror swings up and away, allowing exposure, then instantly returns. Because the photographer sees the scene through the camera lens, the SLR avoids the problem of parallax, the misalignment that occurs when the viewing lens is separated from the taking lens. The large-format camera, taking sheet film, is a direct successor of the early plate cameras and stayed in use for technical, architectural, and industrial work. The earliest cameras produced in significant numbers were plate cameras, using sensitized glass plates, and many photographers used a dark cloth over their heads to focus on a faint ground glass screen. Twin-lens reflex cameras used a pair of nearly identical lenses, one to form the image and one as a viewfinder, arranged with the viewing lens immediately above the taking lens. Rangefinder cameras brought two separate viewfinder windows together on a ground glass screen, and when vertical lines met exactly in the combined image, the subject was in focus. Some forms chased portability above all. The 8x11mm Minox, the only type of camera the company produced from 1937 to 1976, became widely known and was often used for espionage. The Vest Pocket Kodak, sold in two generations between 1912 and 1934, was one of the smallest and best-selling cameras ever made. The instant camera went further still. Polaroid's SX-70 system could make a row of ten shots, engine driven, without removing any cover sheets. These were all built to freeze a single moment, but another branch of the family was learning to capture motion itself.

• 6. Capturing Motion

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  A movie camera records a series of static images in rapid succession, commonly at a rate of 24 frames per second. When the images are combined and displayed in order, the illusion of motion is achieved. The ciné camera, as it is known in Europe, takes each image through an intermittent mechanism, and the frames are later played back in a ciné projector at a set frame rate. A person's visual system merges the separate pictures into movement. The first ciné camera was built around 1888, and by 1890 several types were being manufactured. The standard film size was quickly established as 35mm film, which remained in use until the transition to digital cinematography. Other professional formats include 70mm film and 16mm film, while amateur filmmakers used 9.5mm, 8mm, Standard 8, or Super 8. A professional video camera, often called a television camera, was a different machine, a high-end device for creating electronic moving images rather than recording onto film. These cameras earlier used vacuum tubes and later electronic image sensors. The camcorder folded two machines into one, combining a video camera and a video recorder into a portable, self-contained device. Each of these tools eventually faced the same turning point. Consumers adopted digital cameras in the 1990s, professional video cameras transitioned to digital around the 2000s to 2010s, and movie cameras transitioned to digital in the 2010s.

• 7. From Daguerreotype To Smartphone

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  The introduction of the daguerreotype process in 1839 facilitated commercial camera manufacturing, with various producers contributing diverse designs. Before that, pioneers like Thomas Wedgwood, Nicéphore Niépce, and Henry Fox Talbot first used the camera obscura for chemical experiments. As camera manufacturing became a specialized trade in the 1850s, designs and sizes were standardized. The latter half of the 19th century brought dry plates and roll-film, pushing cameras smaller and cheaper, a shift epitomized by the original Kodak camera, first produced in 1888. After World War I, Germany took the lead in camera development, producing precision-made cameras and launching products such as the Leica camera and the Contax. Eastman Kodak widened access to cinematography for amateurs by producing the first 16-mm and 8-mm reversal safety films. In the second half of the 20th century, Japanese manufacturers in particular advanced the technology. The affordable Ricohflex III TLR arrived in 1952, and the Olympus AutoEye of 1960 was the first 35mm SLR with automatic exposure. Electronics became integral to camera design in the 1970s, evident in Polaroid's SX-70 and Canon's AE-1. Digital camera sales surpassed film cameras in the United States by 2003. The first full-frame digital SLR cameras were developed in Japan from around 2000 to 2002, including the MZ-D by Pentax, the N Digital by Contax's Japanese R6D team, and the EOS-1Ds by Canon. Then the camera left the camera body entirely. In 2000, Sharp introduced the world's first digital camera phone, the J-SH04 J-Phone, in Japan. By the beginning of the 2010s, almost all smartphones had an integrated digital camera. With that shift came computational photography, using algorithms to deliver low-light and HDR photography, optical image stabilization, and depth-sensing, making the smartphone camera easier to use than the dedicated machine it grew out of.