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Queensferry Crossing Aerial. Improve your photography. Small groups per workshop Years of experience with hundreds of participants Catering for every skill level - whether amateur or professional. Browse Workshops. Latest Portfolio Images. Glen Coe Snow - Lagangarbh Cottage. St Andrews Aerial. Mykines, Faroe Islands. Funningur Light, Faroe Islands. River Forth, Stirling. Latest from the Blog. A movie camera or a video camera operates similarly to a still camera, except it 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. However these categories overlap as still cameras are often used to capture moving images in special effects work and many modern cameras can quickly switch between still and motion recording modes. Traditional cameras capture light onto photographic plate or photographic film. Video and digital cameras use an electronic image sensor , usually a charge coupled device CCD or a CMOS sensor to capture images which can be transferred or stored in a memory card or other storage inside the camera for later playback or processing.
A wide range of film and plate formats have been used by cameras. In the early history plate sizes were often specific for the make and model of camera although there quickly developed some standardisation for the more popular cameras. The introduction of roll film drove the standardization process still further so that by the s only a few standard roll films were in use. These included film providing 8, 12 or 16 exposures, film providing 16 or 24 exposures, film providing 8 or 12 exposures principally in Brownie cameras and 35 mm film providing 12, 20 or 36 exposures — or up to 72 exposures in the half-frame format or in bulk cassettes for the Leica Camera range.
It was used for nearly all film-based professional motion picture production. For amateur use, several smaller and therefore less expensive formats were introduced. Traditionally used to "tell the camera" the film speed of the selected film on film cameras, film speed numbers are employed on modern digital cameras as an indication of the system's gain from light to numerical output and to control the automatic exposure system. Film speed is usually measured via the ISO system. The higher the film speed number the greater the film sensitivity to light, whereas with a lower number, the film is less sensitive to light.
On digital cameras, electronic compensation for the color temperature associated with a given set of lighting conditions, ensuring that white light is registered as such on the imaging chip and therefore that the colors in the frame will appear natural. On mechanical, film-based cameras, this function is served by the operator's choice of film stock or with color correction filters.
In addition to using white balance to register natural coloration of the image, photographers may employ white balance to aesthetic end, for example, white balancing to a blue object in order to obtain a warm color temperature. The lens of a camera captures the light from the subject and brings it to a focus on the sensor. The design and manufacture of the lens is critical to the quality of the photograph being taken. The technological revolution in camera design in the 19th century revolutionized optical glass manufacture and lens design with great benefits for modern lens manufacture in a wide range of optical instruments from reading glasses to microscopes.
Pioneers included Zeiss and Leitz. Camera lenses are made in a wide range of focal lengths. They range from extreme wide angle , and standard, medium telephoto. Each lens is best suited to a certain type of photography. The extreme wide angle may be preferred for architecture because it has the capacity to capture a wide view of a building. The normal lens, because it often has a wide aperture, is often used for street and documentary photography. The telephoto lens is useful for sports and wildlife but it is more susceptible to camera shake.
Due to the optical properties of photographic lenses , only objects within a limited range of distances from the camera will be reproduced clearly. The process of adjusting this range is known as changing the camera's focus. There are various ways of focusing a camera accurately. Fixed focus cameras are usually inexpensive types, such as single-use cameras.
The camera can also have a limited focusing range or scale-focus that is indicated on the camera body. The user will guess or calculate the distance to the subject and adjust the focus accordingly. On some cameras this is indicated by symbols head-and-shoulders; two people standing upright; one tree; mountains. Rangefinder cameras allow the distance to objects to be measured by means of a coupled parallax unit on top of the camera, allowing the focus to be set with accuracy. Single-lens reflex cameras allow the photographer to determine the focus and composition visually using the objective lens and a moving mirror to project the image onto a ground glass or plastic micro-prism screen.
Twin-lens reflex cameras use an objective lens and a focusing lens unit usually identical to the objective lens. View cameras use a ground glass screen which is removed and replaced by either a photographic plate or a reusable holder containing sheet film before exposure. Modern cameras often offer autofocus systems to focus the camera automatically by a variety of methods. Some experimental cameras, for example the planar Fourier capture array PFCA , do not require focusing to allow them to take pictures. In conventional digital photography, lenses or mirrors map all of the light originating from a single point of an in-focus object to a single point at the sensor plane.
Each pixel thus relates an independent piece of information about the far-away scene. In contrast, a PFCA does not have a lens or mirror, but each pixel has an idiosyncratic pair of diffraction gratings above it, allowing each pixel to likewise relate an independent piece of information specifically, one component of the 2D Fourier transform about the far-away scene.
Together, complete scene information is captured and images can be reconstructed by computation. Some cameras have post focusing. Post focusing means take the pictures first and then focusing later at the personal computer. The camera uses many tiny lenses on the sensor to capture light from every camera angle of a scene and is called plenoptics technology.
A current plenoptic camera design has 40, lenses working together to grab the optimal picture. On some cameras, the selection of a point in the imaging frame upon which the auto-focus system will attempt to focus. Many Single-lens reflex cameras SLR feature multiple auto-focus points in the viewfinder. Adjustment of the lens opening measured as f-number , which controls the amount of light passing through the lens. The focal length divided by the f-number gives the effective aperture diameter.
The size of the aperture and the brightness of the scene controls the amount of light that enters the camera during a period of time, and the shutter controls the length of time that the light hits the recording surface. Equivalent exposures can be made using a large aperture size with a fast shutter speed and a small aperture with a slow shutter.
Although a range of different shutter devices have been used during the development of the camera only two types have been widely used and remain in use today. The Leaf shutter or more precisely the in-lens shutter is a shutter contained within the lens structure, often close to the diaphragm consisting of a number of metal leaves which are maintained under spring tension and which are opened and then closed when the shutter is released. The exposure time is determined by the interval between opening and closing.
In this shutter design, the whole film frame is exposed at one time. This makes flash synchronisation much simpler as the flash only needs to fire once the shutter is fully open. The focal-plane shutter operates as close to the film plane as possible and consists of cloth curtains that are pulled across the film plane with a carefully determined gap between the two curtains typically running horizontally or consisting of a series of metal plates typically moving vertically just in front of the film plane.
The focal-plane shutter is primarily associated with the single lens reflex type of cameras, since covering the film rather than blocking light passing through the lens allows the photographer to view through the lens at all times except during the exposure itself. Covering the film also facilitates removing the lens from a loaded camera many SLRs have interchangeable lenses. Adjustment of the speed often expressed either as fractions of seconds or as an angle, with mechanical shutters of the shutter to control the amount of time during which the imaging medium is exposed to light for each exposure.
Shutter speed may be used to control the amount of light striking the image plane; 'faster' shutter speeds that is, those of shorter duration decrease both the amount of light and the amount of image blurring from motion of the subject or camera. The slower shutter speeds allow for long exposure shots that are done used to photograph images in very low light including the images of the night sky.
Measurement of exposure so that highlights and shadows are exposed according to the photographer's wishes. Many modern cameras meter and set exposure automatically. Before automatic exposure, correct exposure was accomplished with the use of a separate light metering device or by the photographer's knowledge and experience of gauging correct settings. To translate the amount of light into a usable aperture and shutter speed, the meter needs to adjust for the sensitivity of the film or sensor to light.
This is done by setting the "film speed" or ISO sensitivity into the meter. Camera controls are interrelated due to the similarities in the exposure controls. The total amount of light reaching the film plane the 'exposure' changes with the duration of exposure, aperture of the lens, and on the effective focal length of the lens which in variable focal length lenses, can force a change in aperture as the lens is zoomed. Changing any of these controls can alter the exposure. Many cameras may be set to adjust most or all of these controls automatically.
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This automatic functionality is useful for occasional photographers in many situations. The duration of an exposure is referred to as shutter speed, often even in cameras that do not have a physical shutter, and is typically measured in fractions of a second. It is quite possible to have exposures from one up to several seconds, usually for still-life subjects, and for night scenes exposure times can be several hours.
However, longer shutter speeds blur motion, and shorter shutter speeds freeze motion. Therefore, moving subjects require fast shutter speeds. The effective aperture is expressed by an f-number or f-stop derived from focal ratio , which is proportional to the ratio of the focal length to the diameter of the aperture. Longer focal length lenses will pass less light through the same aperture diameter due to the greater distance the light has to travel; shorter focal length lenses will transmit more light through the same diameter of aperture.
The f-stops that might be found on a typical lens include 2. Image capture can be achieved through various combinations of shutter speed, aperture, and film or sensor speed. Different but related settings of aperture and shutter speed enable photographs to be taken under various conditions of film or sensor speed, lighting and motion of subjects or camera, and desired depth of field. A slower speed film will exhibit less "grain", and a slower speed setting on an electronic sensor will exhibit less "noise", while higher film and sensor speeds allow for a faster shutter speed, which reduces motion blur or allows the use of a smaller aperture to increase the depth of field.
For example, a wider aperture is used for lower light and a lower aperture for more light. If a subject is in motion, then a high shutter speed may be needed. A tripod can also be helpful in that it enables a slower shutter speed to be used.
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The chosen combination affects the final result. The aperture and focal length of the lens determine the depth of field , which refers to the range of distances from the lens that will be in focus. A longer lens or a wider aperture will result in "shallow" depth of field i. This is often useful for isolating subjects from backgrounds as in individual portraits or macro photography. Conversely, a shorter lens, or a smaller aperture, will result in more of the image being in focus.
This is generally more desirable when photographing landscapes or groups of people. With very small apertures, such as pinholes , a wide range of distance can be brought into focus, but sharpness is severely degraded by diffraction with such small apertures. However, as lens technology improves, lenses are becoming capable of making increasingly sharp images at wider apertures. Image capture is only part of the image forming process. Regardless of material, some process must be employed to render the latent image captured by the camera into a viewable image.
With slide film, the developed film is just mounted for projection. Print film requires the developed film negative to be printed onto photographic paper or transparency. Prior to the advent of laser jet and inkjet printers, celluloid photographic negative images had to be mounted in an enlarger which projected the image onto a sheet of light-sensitive paper for a certain length of time usually measured in seconds or fractions of a second.
This sheet then was soaked in a chemical bath of developer to bring out the image followed immediately by a stop bath to neutralize the progression of development and prevent the image from changing further once exposed to normal light. After this, the paper was hung until dry enough to safely handle. This post-production process allowed the photographer to further manipulate the final image beyond what had already been captured on the negative, adjusting the length of time the image was projected by the enlarger and the duration of both chemical baths to change the image's intensity, darkness, clarity, etc.
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This process is still employed by both amateur and professional photographers, but the advent of digital imagery means that the vast majority of modern photographic work is captured digitally and rendered via printing processes that are no longer dependent on chemical reactions to light. Such digital images may be uploaded to an image server e. Every type can then be produced as a hard copy on regular paper or photographic paper via a printer.
Prior to the rendering of a viewable image, modifications can be made using several controls. Many of these controls are similar to controls during image capture, while some are exclusive to the rendering process. Most printing controls have equivalent digital concepts, but some create different effects. For example, dodging and burning controls are different between digital and film processes. A manually inserted blade known as a dark slide allows the film to be covered when changing lenses or film backs.
A blind inside the camera covers the film prior to and after the exposure but is not designed to be able to give accurately controlled exposure times and a leaf shutter that is normally open is installed in the lens. To take a picture, the leaf shutter closes, the blind opens, the leaf shutter opens then closes again, and finally the blind closes and the leaf shutter re-opens the last step may only occur when the shutter is re-cocked.
Using a focal-plane shutter, exposing the whole film plane can take much longer than the exposure time. The exposure time does not depend on the time taken to make the exposure over all, only on the difference between the time a specific point on the film is uncovered and then covered up again.
In fact in practice the curtains do not run at a constant speed as they would in an ideal design, obtaining an even exposure time depends mainly on being able to make the two curtains accelerate in a similar manner. When photographing rapidly moving objects, the use of a focal-plane shutter can produce some unexpected effects, since the film closest to the start position of the curtains is exposed earlier than the film closest to the end position.
Typically this can result in a moving object leaving a slanting image. The direction of the slant depends on the direction the shutter curtains run in noting also that as in all cameras the image is inverted and reversed by the lens, i. Focal-plane shutters are also difficult to synchronise with flash bulbs and electronic flash and it is often only possible to use flash at shutter speeds where the curtain that opens to reveal the film completes its run and the film is fully uncovered, before the second curtain starts to travel and cover it up again.
The forerunner to the photographic camera was the camera obscura. Camera obscura Latin for "dark room" is the natural phenomenon that occurs when an image of a scene at the other side of a screen or for instance a wall is projected through a small hole in that screen and forms an inverted image left to right and upside down on a surface opposite to the opening. The oldest known record of this principle is a description by Han Chinese philosopher Mozi ca.
Mozi correctly asserted the camera obscura image is inverted because light travels inside the camera straight lines from its source. Aristotle discovered that the smaller the hole, the clearer the image is when displayed. In the 11th century, Arab physicist Ibn al-Haytham Alhazen wrote very influential essays about the camera obscura, including experiments with light through a small opening in a darkened room.
Camera obscuras were used as drawing aids since at least circa Since the late 17th century, portable camera obscura devices in tents and boxes were used as drawing aids. Before the development of the photographic camera, it had been known for hundreds of years that some substances, such as silver salts, darkened when exposed to sunlight. These images weren't permanent, however, as Wedgwood didn't employ a fixing mechanism. He ultimately failed at his goal of using the process to create fixed images created by a camera obscura.
It was made using an 8-hour exposure on pewter coated with bitumen. He called this process Daguerreotype , and tried unsuccessfully for a couple years to commercialize it. In the s, the English scientist Henry Fox Talbot independently invented a process to fix camera images using silver salts. Within two years, Talbot developed a two-step process for creating photographs on paper, which he called calotypes. The calotyping process was the first to utilize negative prints, which reverse all values in the photograph — black shows up as white and vice versa.
The first photographic camera developed for commercial manufacture was a daguerreotype camera, built by Alphonse Giroux in By sliding the inner box, objects at various distances could be brought to as sharp a focus as desired. After a satisfactory image had been focused on the screen, the screen was replaced with a sensitized plate.
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A knurled wheel controlled a copper flap in front of the lens, which functioned as a shutter. The early daguerreotype cameras required long exposure times, which in could be from 5 to 30 minutes. After the introduction of the Giroux daguerreotype camera, other manufacturers quickly produced improved variations. Chevalier's camera had a hinged bed, allowing for half of the bed to fold onto the back of the nested box.
In addition to having increased portability, the camera had a faster lens, bringing exposure times down to 3 minutes, and a prism at the front of the lens, which allowed the image to be laterally correct. The Nouvel Appareil Gaudin camera had a metal disc with three differently-sized holes mounted on the front of the lens. Rotating to a different hole effectively provided variable f-stops , letting in different amount of light into the camera. Its design was the most widely used for portraits until Carl Zeiss introduced the anastigmat lens in The American-box camera had beveled edges at the front and rear, and an opening in the rear where the formed image could be viewed on ground glass.
The top of the camera had hinged doors for placing photographic plates. Inside there was one available slot for distant objects, and another slot in the back for close-ups. The lens was focused either by sliding or with a rack and pinion mechanism. The Robert's-type cameras were similar to the American-box, except for having a knob-fronted worm gear on the front of the camera, which moved the back box for focusing. Many Robert's-type cameras allowed focusing directly on the lens mount. The third popular daguerreotype camera in America was the Lewis-type, introduced in , which utilized a bellows for focusing.
The main body of the Lewis-type camera was mounted on the front box, but the rear section was slotted into the bed for easy sliding. Once focused, a set screw was tightened to hold the rear section in place. Daguerreotype cameras formed images on silvered copper plates and images were only able to develop with mercury vapor .
The earliest daguerreotype cameras required several minutes to half an hour to expose images on the plates. By , exposure times were reduced to just a few seconds owing to improvements in the chemical preparation and development processes, and to advances in lens design. The collodion wet plate process that gradually replaced the daguerreotype during the s required photographers to coat and sensitize thin glass or iron plates shortly before use and expose them in the camera while still wet.
Early wet plate cameras were very simple and little different from Daguerreotype cameras, but more sophisticated designs eventually appeared. The Dubroni of allowed the sensitizing and developing of the plates to be carried out inside the camera itself rather than in a separate darkroom. Other cameras were fitted with multiple lenses for photographing several small portraits on a single larger plate, useful when making cartes de visite.
It was during the wet plate era that the use of bellows for focusing became widespread, making the bulkier and less easily adjusted nested box design obsolete. For many years, exposure times were long enough that the photographer simply removed the lens cap , counted off the number of seconds or minutes estimated to be required by the lighting conditions, then replaced the cap. As more sensitive photographic materials became available, cameras began to incorporate mechanical shutter mechanisms that allowed very short and accurately timed exposures to be made.
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The use of photographic film was pioneered by George Eastman , who started manufacturing paper film in before switching to celluloid in His first camera, which he called the " Kodak ," was first offered for sale in It was a very simple box camera with a fixed-focus lens and single shutter speed, which along with its relatively low price appealed to the average consumer. The Kodak came pre-loaded with enough film for exposures and needed to be sent back to the factory for processing and reloading when the roll was finished.
By the end of the 19th century Eastman had expanded his lineup to several models including both box and folding cameras. Films also made possible capture of motion cinematography establishing the movie industry by end of 19th century. In photography, the single-lens reflex camera SLR is provided with a mirror to redirect light from the picture taking lens to the viewfinder prior to releasing the shutter for composing and focusing an image.
When the shutter is released, the mirror swings up and away allowing the exposure of the photographic medium and instantly returns after the exposure. No SLR camera before had this feature, although the mirror on some early SLR cameras was entirely operated by the force exerted on the shutter release and only returned when the finger pressure was released. The earliest cameras produced in significant numbers used sensitised glass plates were plate cameras.
Light entered a lens mounted on a lens board which was separated from the plate by an extendible bellows. Many of these cameras had controls to raise or lower the lens and to tilt it forwards or backwards to control perspective. Focusing of these plate cameras was by the use of a ground glass screen at the point of focus. Because lens design only allowed rather small aperture lenses, the image on the ground glass screen was faint and most photographers had a dark cloth to cover their heads to allow focussing and composition to be carried out more easily.
When focus and composition were satisfactory, the ground glass screen was removed and a sensitised plate put in its place protected by a dark slide. To make the exposure, the dark slide was carefully slid out and the shutter opened and then closed and the dark slide replaced. Glass plates were later replaced by sheet film in a dark slide for sheet film; adaptor sleeves were made to allow sheet film to be used in plate holders.