Editing Camera (section)

== Mechanics ==
[[File:Reflex camera simple labels.svg|thumb|upright=1.2|Basic elements of a modern digital single-lens reflex (SLR) still camera]]
Most cameras capture light from the [[visible spectrum|visible light spectrum]], while specialized cameras capture other portions of the [[electromagnetic spectrum]], such as [[infrared]].<ref>{{cite book |last1=Gustavson |first1=Todd |title=Camera: a history of photography from daguerreotype to digital |publisher=Sterling Publishing Co., Inc |year=2009 |location=New York |isbn=978-1-4027-5656-6}}</ref>{{Rp|vii}}

All cameras use the same basic design: light enters an enclosed box through a [[converging lens|converging or convex lens]] and an image is recorded on a light-sensitive medium.<ref>{{Cite web|title=camera design {{!}} designboom.com|url=https://www.designboom.com/tag/camera-design/|access-date=2021-09-18|website=designboom {{!}} architecture & design magazine|language=en|archive-date=18 September 2021|archive-url=https://web.archive.org/web/20210918121450/https://www.designboom.com/tag/camera-design/|url-status=live}}</ref> A shutter mechanism controls the length of time that light enters the camera.<ref>{{cite book |last1=Young |first1=Hugh D. |last2=Freedman |first2=Roger A. |last3=Ford |first3=A. Lewis |title=Sears and Zemansky's University Physics |edition=12 |publisher=Pearson Addison-Wesley |year=2008 |location=San Francisco, California |isbn=978-0-321-50147-9}}</ref>{{Rp|1182–1183}}

Most cameras also have a viewfinder, which shows the scene to be recorded, along with means to adjust various combinations of [[focus (optics)|focus]], aperture and [[shutter speed]].<ref name="Upton">{{cite book |last1=London |first1=Barbara |last2=Upton |first2=John |last3=Kobré |first3=Kenneth |last4=Brill |first4=Betsy |title=Photography |edition=7 |publisher=Prentice Hall |year=2002 |location=Upper Saddle River, New Jersey |isbn=978-0-13-028271-2}}</ref>{{Rp|4}}

=== Exposure control ===
{{Main|Exposure (photography)}}

==== Aperture ====
{{Main|Aperture}}
[[File: Lenses with different apertures.jpg|thumb|Different apertures of a lens]]

Light enters the camera through an aperture, an opening adjusted by overlapping plates called the aperture ring.<ref name="Columbia">{{Cite encyclopedia|title=camera|encyclopedia=The Columbia Encyclopedia|publisher=Columbia University Press|url=https://www.pin1.harvard.edu/pin/authenticate?__authen_application=HUL_ACC_MGMT_SVC&__hulaccess_gateway=ezproxy&__hulaccess_resource=zorecord&__hulaccess_url=https%3A%2F%2Fsearch.credoreference.com%2Fcontent%2Ftopic%2Fcamera|last=Columbia University|date=2018|editor=Paul Lagasse|edition=8|url-access=subscription}}</ref><ref name="How-Stuff-Works">{{Cite web|title=How Cameras Work|url=https://electronics.howstuffworks.com/camera.htm/printable|access-date=13 December 2019|work=How Stuff Works|date=21 March 2001|archive-date=14 December 2019|archive-url=https://web.archive.org/web/20191214060333/https://electronics.howstuffworks.com/camera.htm/printable|url-status=live}}</ref><ref name="Dawn">Laney, Dawn A. ..BA, MS, CGC, CCRC. “Camera Technologies.” ''Salem Press Encyclopedia of Science'', June 2020. Accessed 6 February 2022.</ref> Typically located in the lens,<ref name="Warren-Camera">{{Cite encyclopedia|title=Camera: An Overview|encyclopedia=Encyclopedia of twentieth-century photography|publisher=Routledge|location=New York|date=2006|editor=Lynne Warren|isbn=978-1-57958-393-4}}</ref> this opening can be widened or narrowed to alter the amount of light that strikes the film or sensor.<ref name="Columbia" />  The size of the aperture can be set manually, by rotating the lens or adjusting a dial or automatically based on readings from an internal light meter.<ref name="Columbia" />

As the aperture is adjusted, the opening expands and contracts in increments called [[f-number|''f-stops'']].{{efn|These f-stops are also referred to as ''f-numbers'', ''stop numbers'', ''steps'' or ''stops''. The f-number is the focal length of the lens divided by the diameter of the effective aperture.}}<ref name="Columbia" /> The smaller the f-stop, the more light is allowed to enter the lens, increasing the exposure. Typically, f-stops range from {{f/}}1.4 to {{f/}}32{{Efn|Theoretically, they can extend to {{f/}}64 or higher.<ref name="Dawn" />}} in standard increments: 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, and 32.<ref name="Britannica-Technology">{{Cite encyclopedia|title=technology of photography|encyclopedia=Britannica Academic|url=https://academic-eb-com.ezp-prod1.hul.harvard.edu/levels/collegiate/article/technology-of-photography/108552#36407.toc|access-date=13 December 2019|url-access=subscription|archive-date=10 November 2023|archive-url=https://web.archive.org/web/20231110043035/https://www.pin1.harvard.edu/cas/login?service=https%3A%2F%2Fkey-idp.iam.harvard.edu%2Fidp%2FAuthn%2FExternal%3Fconversation%3De1s1%26entityId%3Dezp-prod1.hul.harvard.edu%2Flts%2Fezproxyprod%2Fsp#36407.toc|url-status=live}}</ref> The light entering the camera is halved with each increasing increment.<ref name="Warren-Camera" />[[File:Daisies-Focus.jpg|thumb|right|The distance range in which objects appear clear and sharp, called ''[[depth of field]]'', can be adjusted by many cameras. This allows a photographer to control which objects appear in focus, and which do not.|alt=An image of flowers, with one in focus. The background is out of focus.]]

The wider opening at lower f-stops narrows the range of focus so the background is blurry while the foreground is in focus. This [[depth of field]] increases as the aperture closes. A narrow aperture results in a high depth of field, meaning that objects at many different distances from the camera will appear to be in focus.<ref name="Warren-35mm">{{Cite encyclopedia|title=Camera: 35&nbsp;mm|encyclopedia=Encyclopedia of twentieth-century photography|publisher=Routledge|location=New York|date=2006|editor=Lynne Warren|isbn=978-1-57958-393-4}}</ref> What is acceptably in focus is determined by the [[circle of confusion]], the photographic technique, the equipment in use and the degree of magnification expected of the final image.<ref>{{cite book|title=The British Journal Photographic Almanac|date=1956|publisher=Henry Greenwood and Co. Ltd|pages= 468–471}}</ref>

==== Shutter ====
{{Main|Shutter (photography)}}

The shutter, along with the aperture, is one of two ways to control the amount of light entering the camera. The [[Shutter (photography)|shutter]] determines the duration that the light-sensitive surface is exposed to light. The shutter opens, light enters the camera and exposes the film or sensor to light, and then the shutter closes.<ref name="Warren-Camera" /><ref name="Focal">{{Cite encyclopedia|publisher=Elsevier|isbn=978-0-240-80740-9|pages=770–771|last=Rose|first=B|title=The Camera Defined|encyclopedia=The Focal Encyclopedia of Photography|access-date=12 December 2019|date=2007|doi=10.1016/B978-0-240-80740-9.50152-5|url=https://linkinghub.elsevier.com/retrieve/pii/B9780240807409501525|archive-date=14 December 2019|archive-url=https://web.archive.org/web/20191214060334/https://linkinghub.elsevier.com/retrieve/pii/B9780240807409501525|url-status=live|url-access=subscription}}</ref>

There are two types of mechanical shutters: the leaf-type shutter and the focal-plane shutter. The leaf-type uses a circular iris diaphragm maintained under spring tension inside or just behind the lens that rapidly opens and closes when the shutter is released.<ref name="Britannica-Technology" /> [[File: Focal-plane shutter.jpg|thumb|A focal-plane shutter. In this shutter, the metal shutter blades travel vertically.]]
More commonly, a [[focal-plane shutter]] is used.<ref name="Warren-Camera" /> This shutter operates close to the film plane and employs metal plates or cloth curtains with an opening that passes across the light-sensitive surface. The curtains or plates have an opening that is pulled across the film plane during exposure. The focal-plane shutter is typically used in single-lens reflex (SLR) cameras, since covering the film (rather than blocking the light passing through the lens) allows the photographer to view the image through the lens at all times, except during the exposure itself. Covering the film also facilitates removing the lens from a loaded camera, as many SLRs have interchangeable lenses.<ref name="Columbia" /><ref name="Britannica-Technology" />

A [[digital camera]] may use a mechanical or electronic shutter, the latter of which is common in smartphone cameras. Electronic shutters either record data from the entire sensor simultaneously (a global shutter) or record the data line by line across the sensor (a rolling shutter).<ref name="Columbia" /> In movie cameras, a rotary shutter opens and closes in sync with the advancement of each frame of film.<ref name="Columbia" /><ref>{{Cite encyclopedia|title=Motion-picture camera|encyclopedia=Encyclopedia Britannica|access-date=12 December 2019|url=https://www-britannica-com.ezp-prod1.hul.harvard.edu/technology/motion-picture-camera}}{{dead link|date=November 2023}}</ref>

The duration for which the shutter is open is called the ''[[shutter speed]]'' or ''exposure time''. Typical exposure times can range from one second to 1/1,000 of a second, though longer and shorter durations are not uncommon. In the early stages of photography, exposures were often several minutes long. These long exposure times often resulted in blurry images, as a single object is recorded in multiple places across a single image for the duration of the exposure. To prevent this, shorter exposure times can be used. Very short exposure times can capture fast-moving action and eliminate motion blur.<ref name="Philip's">{{Cite encyclopedia|publisher=Philip's|isbn=978-0-19-954609-1|title=Camera|encyclopedia=World Encyclopedia|access-date=12 December 2019|url=https://archive.org/details/worldencyclopedi00oxfo|url-access=registration|year=2004}}</ref><ref name="Britannica-Technology" /><ref name="Columbia" /><ref name="Warren-Camera" /> However, shorter exposure times require more light to produce a properly exposed image, so shortening the exposure time is not always possible.

Like aperture settings, exposure times increment in powers of two. The two settings determine the exposure value (EV), a measure of how much light is recorded during the exposure. There is a direct relationship between the exposure times and aperture settings so that if the exposure time is lengthened one step, but the aperture opening is also narrowed one step, then the amount of light that contacts the film or sensor is the same.<ref name="Warren-Camera" />

==== Light meter ====
{{Main|Light meter}}

[[File: Sekonic L-358 Flash Master.jpg|thumb|A handheld digital light meter showing an exposure of 1/200th at an aperture of f/11, at ISO 100. The light sensor is on top, under the white diffusing hemisphere.]]
In most modern cameras, the amount of light entering the camera is measured using a built-in light meter or exposure meter.{{Efn|Some photographers use handheld [[exposure meter]]s independent of the camera and use the readings to manually set the exposure settings on the camera.<ref name="Britannica-Camera" />|name=|}} Taken through the lens (called ''{{Abbr|TTL|through the lens}} metering''), these readings are taken using a panel of light-sensitive [[semiconductor]]s.<ref name="How-Stuff-Works" /> They are used to calculate optimal exposure settings. These settings are typically determined automatically as the reading is used by the camera's [[microprocessor]]. The reading from the light meter is incorporated with aperture settings, exposure times, and film or sensor sensitivity to calculate the optimal exposure.{{Efn|Film canisters typically contain a DX code that can be read by modern cameras so that the camera's computer knows the sensitivity of the film, the ISO.<ref name="Warren-Camera" />]|name=|}}

[[Light meter]]s typically average the light in a scene to 18% middle gray. More advanced cameras are more nuanced in their metering—weighing the center of the frame more heavily (center-weighted metering), considering the differences in light across the image (matrix metering), or allowing the photographer to take a light reading at a specific point within the image (spot metering).<ref name="Warren-35mm" /><ref name="Philip's" /><ref name="Britannica-Camera">{{Cite encyclopedia|title=camera|encyclopedia=Britannica Academic|url=https://academic-eb-com.ezp-prod1.hul.harvard.edu/levels/collegiate/article/camera/18803|access-date=12 December 2019|url-access=subscription|archive-date=10 November 2023|archive-url=https://web.archive.org/web/20231110042914/https://www.pin1.harvard.edu/cas/login?service=https%3A%2F%2Fkey-idp.iam.harvard.edu%2Fidp%2FAuthn%2FExternal%3Fconversation%3De1s1%26entityId%3Dezp-prod1.hul.harvard.edu%2Flts%2Fezproxyprod%2Fsp|url-status=live}}</ref><ref name="Columbia" />

=== Lens ===
{{Main|Camera lens|Photographic lens design}}
A camera lens is an assembly of multiple optical elements, typically made from high-quality glass.<ref name="Cambridge-in-Color">{{Cite web |title=Understanding Camera Lenses |url=https://www.cambridgeincolour.com/tutorials/camera-lenses.htm |accessdate=2019-12-13 |work=Cambridge in Color |archive-date=19 June 2023 |archive-url=https://web.archive.org/web/20230619170605/https://www.cambridgeincolour.com/tutorials/camera-lenses.htm |url-status=live }}</ref> Its primary function is to focus light onto a camera's film or digital sensor, thereby producing an image.<ref name="How-Stuff-Works" /> This process significantly influences image quality, the overall appearance of the photo, and which parts of the scene are brought into focus.<ref name="Cambridge-in-Color" />

A camera lens is constructed from a series of lens elements, small pieces of glass arranged to form an image accurately on the light-sensitive surface. Each element is designed to reduce [[Optical aberration|optical aberrations]], or distortions, such as [[chromatic aberration]] (a failure of the lens to focus all colors at the same point), [[vignetting]] (darkening of image corners), and [[Distortion (optics)|distortion]] (bending or warping of the image). The degree of these distortions can vary depending on the subject of the photo.<ref name="Cambridge-in-Color" />

The [[focal length]] of the lens, measured in millimeters, plays a critical role as it determines how much of the scene the camera can capture and how large the objects appear. Wide-angle lenses provide a broad view of the scene, while telephoto lenses capture a narrower view but magnify the objects. The focal length also influences the ease of taking clear pictures handheld, with longer lengths making it more challenging to avoid blur from small camera movements.<ref name="Cambridge-in-Color" />

Two primary types of lenses include zoom and prime lenses. A zoom lens allows for changing its focal length within a certain range, providing the convenience of adjusting the scene capture without moving the camera or changing the lens. A prime lens, in contrast, has a fixed focal length. While less flexible, prime lenses often provide superior image quality, are typically lighter, and perform better in low light.<ref name="Cambridge-in-Color" />

Focus involves adjusting the lens elements to sharpen the image of the subject at various distances.<ref>{{Cite book |last1=Adams |first1=Ansel |title=The camera |last2=Baker |first2=Robert |date=1980 |publisher=Little, Brown |isbn=978-0-8212-1092-5 |location=Boston}}</ref> The focus is adjusted through the focus ring on the lens, which moves the lens elements closer or further from the sensor. [[Autofocus]] is a feature included in many lenses, which uses a motor within the lens to adjust the focus quickly and precisely based on the lens's detection of contrast or phase differences. This feature can be enabled or disabled using switches on the lens body.<ref name="How-Stuff-Works" />

Advanced lenses may include mechanical [[image stabilization]] systems that move lens elements or the image sensor itself to counteract camera shake, especially beneficial in low-light conditions or at slow shutter speeds.<ref name="Cambridge-in-Color" /> Lens hoods, filters, and caps are accessories used alongside a lens to enhance image quality, protect the lens, or achieve specific effects.<ref name="How-Stuff-Works" />

=== Viewfinder ===
The camera's viewfinder provides a real-time approximation of what will be captured by the sensor or film. It assists photographers in aligning, focusing, and adjusting the composition, lighting, and exposure of their shots, enhancing the accuracy of the final image.<ref name="Warren-Camera" />

Viewfinders fall into two primary categories: optical and electronic. Optical viewfinders, commonly found in Single-Lens Reflex (SLR) cameras, use a system of mirrors or prisms to reflect light from the lens to the viewfinder, providing a clear, real-time view of the scene. Electronic viewfinders, typical in mirrorless cameras, project an electronic image onto a small display, offering a wider range of information such as live exposure previews and histograms, albeit at the cost of potential lag and higher battery consumption.<ref name="Columbia" /> Specialized viewfinder systems exist for specific applications, like [[Subminiature photography|subminiature cameras]] for spying or [[underwater photography]].<ref name="Focal" />

[[Stellar parallax|Parallax error]], resulting from misalignment between the viewfinder and lens axes, can cause inaccurate representations of the subject's position. While negligible with distant subjects, this error becomes prominent with closer ones. Some viewfinders incorporate parallax-compensating devices to mitigate that issue.<ref name="Britannica-Technology" />

=== Film and sensor ===
Image capture in a camera occurs when light strikes a light-sensitive surface: [[photographic film]] or a [[digital sensor]].<ref name="Focal" /> Housed within the camera body, the film or sensor records the light's pattern when the shutter is briefly opened to allow light to pass during the exposure.<ref name="Warren-35mm" />

Loading film into a film camera is a manual process. The film, typically housed in a cartridge, is loaded into a designated slot in the camera. One end of the film strip, the film leader, is manually threaded onto a take-up spool. Once the back of the camera is closed, the film advance lever or knob is used to ensure the film is correctly placed. The photographer then winds the film, either manually or automatically depending on the camera, to position a blank portion of the film in the path of the light. Each time a photo is taken, the film advance mechanism moves the exposed film out of the way, bringing a new, unexposed section of film into position for the next shot.<ref name="Warren-35mm" />

The film must be advanced after each shot to prevent [[Multiple exposure|double exposure]] — where the same section of film is exposed to light twice, resulting in overlapped images. Once all frames on the film roll have been exposed, the film is rewound back into the cartridge, ready to be removed from the camera for developing.<ref name="Focal" />

In digital cameras, sensors typically comprise [[Charge-coupled device|Charge-Coupled Devices (CCDs)]] or Complementary Metal-Oxide-Semiconductor (CMOS) chips, both of which convert incoming light into electrical charges to form digital images.<ref name="Columbia" /> CCD sensors, though power-intensive, are recognized for their excellent light sensitivity and image quality. Conversely, CMOS sensors offer individual pixel readouts, leading to less power consumption and faster frame rates, with their image quality having improved significantly over time.

Digital cameras convert light into electronic data that can be directly processed and stored. The volume of data generated is dictated by the sensor's size and properties, necessitating storage media such as [[CompactFlash|Compact Flash]], [[Memory Stick|Memory Sticks]], and [[SD card|SD (Secure Digital) cards]].<ref name="Focal" /> Modern digital cameras typically feature a built-in monitor for immediate image review and adjustments.<ref name="Columbia" /> Digital images are also more readily handled and manipulated by computers, offering a significant advantage in terms of flexibility and post-processing potential over traditional film.<ref name="Focal" />

=== Camera accessories ===
==== Flash ====
A [[Flash (photography)|flash]] provides a short burst of bright light during exposure and is a commonly used artificial light source in photography. Most modern flash systems use a battery-powered high-voltage discharge through a gas-filled tube to generate bright light for a very short time (1/1,000 of a second or less).{{Efn|The older type of disposable flashbulb uses an aluminum or zirconium wire in a glass tube filled with oxygen. During the exposure, the wire is burned away, producing a bright flash.<ref name="Britannica-Camera" /> |name=|}}<ref name="Britannica-Camera" />

Many flash units measure the light reflected from the flash to help determine the appropriate duration of the flash. When the flash is attached directly to the camera—typically in a slot at the top of the camera (the flash shoe or hot shoe) or through a cable—activating the shutter on the camera triggers the flash, and the camera's internal light meter can help determine the duration of the flash.<ref name="Britannica-Camera" /><ref name="Warren-35mm" />

Additional flash equipment can include a [[Diffuser (optics)|light diffuser]], mount and stand, reflector, [[soft box]], trigger and cord.

==== Other accessories ====
Accessories for cameras are mainly used for care, protection, special effects, and functions.
* [[Lens hood]]: used on the end of a lens to block the sun or other light source to prevent glare and lens flare (see also [[matte box]]).
* [[Lens cap]]: covers and protects the camera lens when not in use.
* [[Lens adapter]]: allows the use of lenses other than those for which the camera was designed.
* [[Photographic filter|Filter]]: allows artificial colors or changes light density.
* [[Extension tube|Lens extension tube]]: allows close focus in [[macro photography]].
* Care and protection: including camera case and cover, maintenance tools, and screen protector.
* [[Camera monitor]]: provides an off-camera view of the composition with a brighter and more colorful screen, and typically exposes more advanced tools such as framing guides, [[focus peaking]], [[zebra patterning|zebra stripes]], [[waveform monitor]]s (oftentimes as an "RGB parade"), [[vectorscope]]s and [[false color]] to highlight areas of the image critical to the photographer.
* [[Tripod (photography)|Tripod]]: primarily used for keeping the camera steady while recording video, doing a long exposure, and [[Time-lapse photography|time-lapse]] photography.
* Microscope adapter: used to connect a camera to a microscope to photograph what the microscope is examining.
* [[Bulb (photography)|Cable release]]: used to remotely control the shutter using a remote shutter button that can be connected to the camera via a cable. It can be used to lock the shutter open for the desired period, and it is also commonly used to prevent the camera shake from pressing the built-in camera shutter button.
* [[Dew shield]]: prevents moisture build-up on the lens.
* [[UV filter]]: can protect the front element of a lens from scratches, cracks, smudges, dirt, dust, and moisture while keeping a minimum impact on image quality.
* Battery and sometimes a charger.
[[Large format|Large format cameras]] use special equipment that includes a magnifier loupe, view finder, angle finder, and focusing rail/truck. Some professional SLRs can be provided with interchangeable [[Viewfinder|finders]] for eye-level or waist-level focusing, [[focusing screen]]s, eyecup, data backs, [[Motor drive|motor-drives]] for film transportation or external battery packs.