Editing Digital camera (section)

== Image sensors ==
{{Further|Image sensor}}
The two major types of digital image sensors are CCD and CMOS. A CCD sensor has one amplifier for all the pixels, while each pixel in a CMOS active-pixel sensor has its own amplifier.<ref>{{cite web |url=http://www.ebay.de/gds/What-Is-the-Difference-Between-a-CCD-and-CMOS-Video-Camera-/10000000177630865/g.html |title=What Is the Difference Between a CCD and CMOS Video Camera |access-date=March 26, 2014 |archive-date=March 26, 2014 |archive-url=https://web.archive.org/web/20140326043747/http://www.ebay.de/gds/What-Is-the-Difference-Between-a-CCD-and-CMOS-Video-Camera-/10000000177630865/g.html |url-status=live }}</ref> Compared to CCDs, CMOS sensors use less power. Cameras with a small sensor use a [[back-illuminated sensor|back-side-illuminated]] CMOS (BSI-CMOS) sensor. The [[image processing]] capabilities of the camera determine the outcome of the final image quality much more than the sensor type.<ref>{{Cite book|last=Nakamura|first=Junichi|url=https://books.google.com/books?id=UY6QzgzgieYC&q=scholarly+articles+on+basic+DSCs+camera&pg=PP1|title=Image Sensors and Signal Processing for Digital Still Cameras|date=2017-12-19|publisher=CRC Press|isbn=978-1-4200-2685-6|language=en}}</ref><ref>{{cite web |url=http://www.cnet.com/news/why-the-iphone-4-takes-good-low-light-photos-bsi-cmos-sensors-explained/ |title=Why the iPhone 4 takes good low-light photos: BSI CMOS sensors explained! |author=Joshua Goldman |access-date=September 29, 2014 |archive-date=September 28, 2014 |archive-url=https://web.archive.org/web/20140928103103/http://www.cnet.com/news/why-the-iphone-4-takes-good-low-light-photos-bsi-cmos-sensors-explained/ |url-status=live }}</ref>

=== Sensor resolution ===

The [[Image resolution|resolution]] of a digital camera is often limited by the [[image sensor]] that turns light into discrete signals. The brighter the image at a given point on the sensor, the larger the value that is read for that pixel.
Depending on the physical structure of the sensor, a [[color filter array]] may be used, which requires [[demosaicing]] to recreate a [[Color image|full-color image]]. The number of pixels in the sensor determines the camera's "[[pixel count]]".
In a typical sensor, the pixel count is the product of the number of rows and the number of columns. For example, a 1,000 by 1,000-pixel sensor would have 1,000,000 pixels, or 1 [[megapixel]].

==== Resolution options ====
Firmwares' resolution selector allows the user to optionally lower the resolution to reduce the file size per picture and extend lossless [[digital zoom]]ing. The bottom resolution option is typically [[640×480]] pixels (0.3 megapixels).<ref>{{Cite web |title=Megapixel Camera - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/computer-science/megapixel-camera |access-date=2024-07-13 |website=www.sciencedirect.com}}</ref>

A lower resolution extends the number of remaining photos in free space, postponing the exhaustion of space storage, which is of use where no further data storage device is available and for captures of lower significance, where the benefit from less space storage consumption outweighs the disadvantage from reduced detail.<ref>{{cite web |title=Advantages and Disadvantages of Low vs High Resolution Cameras |url=https://photographylife.com/advantages-and-disadvantages-of-low-vs-high-resolution-cameras |website=Photography Life |date=19 June 2015 |access-date=10 April 2021 |archive-date=10 April 2021 |archive-url=https://web.archive.org/web/20210410212325/https://photographylife.com/advantages-and-disadvantages-of-low-vs-high-resolution-cameras |url-status=live }}</ref>

=== Image sharpness ===
An image's sharpness is presented through the crisp detail, defined lines, and its depicted contrast. Sharpness is a factor of multiple systems throughout the DSLR camera by its [[Film speed|ISO]], resolution, lens, and the lens settings, the environment of the image, and its post-processing. Images have a possibility of being too sharp, but they can never be too in focus.

A digital camera resolution is determined by a digital sensor. The digital sensor indicates a high level of sharpness can be produced through the amount of noise and grain that is tolerated through the lens of the camera. Resolution within the field of digital stills and digital movies is indicated through the camera's ability to determine detail based on the distance, which is then measured by frame size, pixel type, number, and organization. Although some DSLR cameras have limited resolutions, it is almost impossible to not have the proper sharpness for an image. The ISO choice when taking a photo affects the quality of the image, as high ISO settings equate to an image that is less sharp due to the increased amount of noise allowed into the image, along with too little noise, which can also produce an image that is not sharp.<ref>{{Cite book |last=Andersson |first=Barry |title=The DSLR filmmaker's handbook: real-world production techniques |date=2012 |others=Janie L. Geyen |isbn=978-1-118-98350-8 |location=Indianapolis, IN |oclc=904979226}}</ref>

=== Methods of image capture ===
{{Unreferenced section|date=December 2019}}[[File:Ccd-sensor.jpg|At the heart of a digital camera is a [[charge-coupled device|CCD]] or a [[Active pixel sensor|CMOS]] image sensor.|thumb|upright]]
[[File:Partly disassembled Lumix digital camera.jpg|thumb|Digital camera, partially disassembled. The lens assembly (bottom right) is removed but the sensor (top right) can still capture an image, as seen on the LCD screen (bottom left).]]Since the first digital backs were introduced, there have been three main methods of capturing the image, each based on the hardware configuration of the sensor and color filters.

''Single-shot'' capture systems use either one sensor chip with a [[Bayer filter]] mosaic, or three separate image sensors (one each for the [[primary additive colors]] red, green, and blue) which are exposed to the same image via a [[beam splitter]] (see [[Three-CCD camera]]).

''Multi-shot'' exposes the sensor to the image in a sequence of three or more openings of the lens [[aperture]]. There are several methods of application of the multi-shot technique. The most common was originally to use a single image sensor with three filters passed in front of the sensor in sequence to obtain the additive color information. Another multiple-shot method is called [[microscanning]]. This method uses a single sensor chip with a Bayer filter and physically moves the sensor on the focus plane of the lens to construct a higher resolution image than the native resolution of the chip. A third version combines these two methods without a Bayer filter on the chip.

The third method is called ''scanning'' because the sensor moves across the focal plane much like the sensor of an [[image scanner]]. The ''linear'' or ''tri-linear'' sensors in scanning cameras utilize only a single line of photosensors, or three lines for the three colors. Scanning may be accomplished by moving the sensor (for example, when using [[color co-site sampling]]) or by rotating the whole camera. A digital [[rotating line camera]] offers images consisting of a total resolution that is very high.

Improvements in single-shot cameras and image file processing at the beginning of the 21st century made single-shot cameras almost completely dominant, even in high-end commercial photography.

=== Filter mosaics, interpolation, and aliasing ===
[[File:Bayer pattern on sensor.svg|thumb|left|The Bayer arrangement of color filters on the pixel array of an image sensor.]]
Most current {{Clarify timeframe|date=February 2020}} consumer digital cameras use a Bayer filter mosaic in combination with an optical [[anti-aliasing filter]] to reduce the aliasing due to the reduced sampling of the different primary-color images.
A demosaicing algorithm is used to [[interpolation|interpolate]] color information to create a full array of RGB image data.

Cameras that use a beam-splitter single-shot [[3CCD]] approach, three-filter multi-shot approach, color co-site sampling or [[Foveon X3 sensor]] do not use anti-aliasing filters, nor demosaicing.


[[Firmware]] in the camera, or a software in a raw converter program such as [[Adobe DNG Converter|Adobe Camera Raw]], interprets the raw data from the sensor to obtain a full-color image, because the [[RGB color model]] requires three intensity values for each pixel: one each for the red, green, and blue (other color models, when used, also require three or more values per pixel).
A single sensor element cannot simultaneously record these three intensities, so a color filter array (CFA) must be used to selectively filter a particular color for each pixel.

The Bayer filter pattern is a repeating 2x2 [[mosaic]] pattern of light filters, with green ones at opposite corners and red and blue in the other two positions. The high proportion of green takes advantage of the properties of the human visual system, which determines brightness mostly from green and is far more sensitive to brightness than to hue or saturation. Sometimes a 4-color filter pattern is used, often involving two different hues of green. This provides potentially more accurate color, but requires a slightly more complicated interpolation process.<ref>{{Cite journal |last1=Cheremkhin |first1=P A |last2=Lesnichii |first2=V V |last3=Petrov |first3=N V |date=2014-09-17 |title=Use of spectral characteristics of DSLR cameras with Bayer filter sensors |journal=Journal of Physics: Conference Series |volume=536 |issue=1 |page=012021 |doi=10.1088/1742-6596/536/1/012021 |bibcode=2014JPhCS.536a2021C |s2cid=31560384 |issn=1742-6588|doi-access=free }}</ref>

The color intensity values not captured for each pixel can be [[interpolate]]d from the values of adjacent pixels which represent the color being calculated.<ref>{{Cite book|last=Malvar|first=Henrique|title=High Quality Linear Interpolation for Demosaicing of Bayer-Patterned Color Images|year=2004}}</ref>

=== Sensor size and angle of view ===
{{Unreferenced section|date=December 2019}}
Cameras with digital image sensors that are smaller than the typical 35&nbsp;mm film size have a smaller field or [[angle of view]] when used with a lens of the same [[focal length]]. This is because the angle of view is a function of both focal length and the sensor or film size used.

[[File:kids 50mm 100mm.jpg|right|thumb|Image illustrating crop factors for some common digital image sensor formats]]

The [[crop factor]] is relative to the [[135 film|35mm film format]]. If a smaller sensor is used, as in most digicams, the field of view is cropped by the sensor to smaller than the 35&nbsp;mm full-frame format's field of view. This narrowing of the field of view may be described as crop factor, a factor by which a longer focal length lens would be needed to get the same field of view on a 35&nbsp;mm film camera. [[Full-frame digital SLR]]s utilize a sensor of the same size as a frame of 35&nbsp;mm film.

Common values for field of view crop in DSLRs using active pixel sensors include 1.3x for some [[Canon Inc.|Canon]] (APS-H) sensors, 1.5x for [[Sony]] APS-C sensors used by Nikon, [[Pentax]] and [[Konica Minolta]] and for Fujifilm sensors, 1.6 (APS-C) for most Canon sensors, ~1.7x for [[Sigma Corporation|Sigma]]'s [[Foveon]] sensors and 2x for [[Kodak]] and Panasonic 4/3-inch sensors currently used by [[Olympus company|Olympus]] and Panasonic. Crop factors for non-SLR consumer compact and [[bridge digital camera|bridge]] cameras are larger, frequently 4x or more.

{{further|Image sensor format}}

[[File:SensorSizes.svg|thumb|right|Relative sizes of sensors used in most current digital cameras.]]

{| style="text-align:center;" class="wikitable"
|+ Table of sensor sizes<ref>{{cite web | url=http://www.dpreview.com/learn/?/Glossary/Camera_System/sensor_sizes_01.htm | title=Sensor sizes | first=Vincent | last=Bockaert | website=[[Digital Photography Review]] | access-date=2007-04-03 | archive-date=2013-01-05 | archive-url=https://web.archive.org/web/20130105032905/http://www.dpreview.com/learn/?%2FGlossary%2FCamera_System%2Fsensor_sizes_01.htm | url-status=live }}</ref>
|-
! Type !! Width (mm) !! Height (mm) !! Size (mm²)
|-
| 1/3.6" || 4.00 || 3.00 || 12.0
|-
| 1/3.2" || 4.54 || 3.42 || 15.5
|-
| 1/3" || 4.80 || 3.60 || 17.3
|-
| 1/2.7" || 5.37 || 4.04 || 21.7
|-
| 1/2.5" || 5.76 || 4.29 || 24.7
|-
| 1/2.3" || 6.16 || 4.62 || 28.5
|-
| 1/2" || 6.40 || 4.80 || 30.7
|-
| 1/1.8" || 7.18 || 5.32 || 38.2
|-
| 1/1.7" || 7.60 || 5.70 || 43.3
|-
| 2/3" || 8.80 || 6.60 || 58.1
|-
| 1" || 12.8 || 9.6 || 123
|-
| [[Four Thirds system|4/3"]] || 18.0 || 13.5 || 243
|-
| [[APS-C]] || 25.1 || 16.7 || 419
|-
| [[135 film|35 mm]] || 36 || 24 || 864
|-
| Back || 48 || 36 || 1728
|}

=== Sensor resolution ===
The [[Image resolution|resolution]] of a digital camera is often limited by the [[image sensor]] that turns light into discrete signals. The brighter the image at a given point on the sensor, the larger the value that is read for that pixel. Depending on the physical structure of the sensor, a [[color filter array]] may be used, which requires [[demosaicing]] to recreate a [[Color image|full-color image]]. The number of pixels in the sensor determines the camera's "[[pixel count]]". In a typical sensor, the pixel count is the product of the number of rows and the number of columns. '''Pixels are square and is often equal to 1''', for example, a 1,000 by 1,000-pixel sensor would have 1,000,000 pixels, or 1 [[megapixel]]. On full-frame sensors (i.e., 24 mm 36 mm), some cameras propose images with 20–25 million pixels that were captured by 7.5–m [[Photosite|photosites]], or a surface that is 50 times larger.  <ref>{{Cite book |last=Maitre |first=Henri |title=From Photon to Pixel. |date=2017 |publisher=John Wiley & Sons, Incorporated |isbn=978-1-119-40243-5 |edition=2nd |location=Newark |oclc=975225434}}</ref>

[[File:Cross section of a DSLR camera.png|left|thumb|Cross section of a DSLR camera.]]