Editing Normal lens (section)

==Typical normal focal lengths for different formats==

===Film still===
[[File:Normal Lenses 7253.jpg|thumb|Four "normal" lenses for the 35&nbsp;mm format.]]
Typical normal lenses for various [[film format]]s for photography are:{{citation needed|date=April 2017}}

{| class="wikitable"
|-
! Film format !! Image dimensions !! Image diagonal !! Normal lens focal length
|-
| 9.5&nbsp;mm [[Minox]]
| 8 × 11&nbsp;mm
| 13.6&nbsp;mm
| 15&nbsp;mm
|-
| Half-frame
| 24 × 18&nbsp;mm
| 30&nbsp;mm
| 30&nbsp;mm
|-
| [[Advanced Photo System|APS]] C
| 16.7 × 25.1&nbsp;mm
| 30.1&nbsp;mm
| 28&nbsp;mm, 30&nbsp;mm
|-
| [[135 film|135]], 35&nbsp;mm
| 24 × 36&nbsp;mm
| 43.3&nbsp;mm
| 40&nbsp;mm, 50&nbsp;mm, 55&nbsp;mm
|-
| [[120 film|120]]/[[220 film|220]], 6 × 4.5 (645)
| 56 × 42&nbsp;mm
| 71.8&nbsp;mm
| 75&nbsp;mm
|-
| 120/220, 6 × 6
| 56 × 56&nbsp;mm
| 79.2&nbsp;mm
| 80&nbsp;mm
|-
| 120/220, 6 × 7
| 56 × 68&nbsp;mm
| 88.1&nbsp;mm
| 90&nbsp;mm
|-
| 120/220, 6 × 9
| 56 × 84&nbsp;mm
| 101.0&nbsp;mm
| 105&nbsp;mm
|-
| 120/220, 6 × 12
| 56 × 112&nbsp;mm
| 125.0&nbsp;mm
| 120&nbsp;mm
|-
| 120/220, 6 x 17
| 56 x 168&nbsp;mm
| 177.1&nbsp;mm
| 180&nbsp;mm
|-
| [[large format]] 4 × 5 [[sheet film]]
| 93 × 118&nbsp;mm (image area)
| 150.2&nbsp;mm
| 150&nbsp;mm
|-
| large format 5 × 7 sheet film
| 120 × 170&nbsp;mm (image area)
| 208.0&nbsp;mm
| 210&nbsp;mm
|-
| large format 8 × 10 sheet film
| 194 × 245&nbsp;mm (image area)
| 312.5&nbsp;mm
| 300&nbsp;mm
|-
|}

For a [[135 film|35&nbsp;mm]] [[camera]] with a diagonal of 43&nbsp;mm, the most commonly used ''normal'' lens is 50&nbsp;mm, but focal lengths between about 40 and 58&nbsp;mm are also considered ''normal''. The 50&nbsp;mm focal length was chosen by [[Oskar Barnack]], the creator of the [[Leica Camera|Leica camera]].<ref>{{cite journal |last1=Rimmasch |first1=Paul |title=Lens Testing: Reassessing the 50 mm Rule |journal=Journal of Forensic Identification |date=July 2017 |volume=67 |issue=3 |pages=323–340}}</ref><ref>{{cite journal |last1=Li |first1=Xiang |last2=Liu |first2=Jianzheng |last3=Baron |first3=Jessica |last4=Luu |first4=Khoa |last5=Patterson |first5=Eric |title=Evaluating effects of focal length and viewing angle in a comparison of recent face landmark and alignment methods |journal=EURASIP Journal on Image and Video Processing |date=March 2021 |volume=2021 |issue=1 |doi=10.1186/s13640-021-00549-3|s2cid=232414675 |doi-access=free }}</ref>

Note that the angle of view also depends on the [[aspect ratio (image)|aspect ratio]]. For example, a "normal" lens on 35&nbsp;mm does not have the same view as a "normal" lens on [[645 film|645]].{{citation needed|date=April 2017}}

===Digital still===
{{Also|Image sensor format#Table of sensor formats and sizes}}
In [[digital photography]], many smaller sensor sizes are specified in terms such as 1" or 2/3".
These measurements do not correspond directly to dimensions of the sensor, but rather to dimensions of an equivalent [[Video camera tube#Size|video camera tube (VCT)]].
The normal lens focal length is roughly 2/3 of the video camera tube diameter.

{| class="wikitable"
|-
! Sensor type !! equiv. VCT diameter !! Image dimensions !! Image diagonal !! Normal lens focal length
|-
| 1/3.6"
| 7.1&nbsp;mm
| 3.0 × 4.0&nbsp;mm
| 5.0&nbsp;mm
| 5&nbsp;mm
|-
| 1/3.2"
| 7.9&nbsp;mm
| 3.4 × 4.5&nbsp;mm
| 5.7&nbsp;mm
| 5.7&nbsp;mm
|-
| 1/3"
| 8.5&nbsp;mm
| 3.6 × 4.8&nbsp;mm
| 6.0&nbsp;mm
| 6&nbsp;mm
|-
| 1/2.7"
| 9.4&nbsp;mm
| 4.0 × 5.4&nbsp;mm
| 6.7&nbsp;mm
| 6.7&nbsp;mm
|-
| 1/2.5"
| 10.2&nbsp;mm
| 4.3 × 5.8&nbsp;mm
| 7.2&nbsp;mm
| 7&nbsp;mm
|-
| 1/2"
| 12.7&nbsp;mm
| 4.8 × 6.4&nbsp;mm
| 8.0&nbsp;mm
| 8&nbsp;mm
|-
| 1/1.8"
| 14.1&nbsp;mm
| 5.3 × 7.2&nbsp;mm
| 8.9&nbsp;mm
| 9&nbsp;mm
|-
| 1/1.7"
| 14.9&nbsp;mm
| 5.7 × 7.6&nbsp;mm
| 9.5&nbsp;mm
| 9.5&nbsp;mm
|-
| 2/3"
| 16.9&nbsp;mm
| 6.6 × 8.8&nbsp;mm
| 11.0&nbsp;mm
| 11&nbsp;mm
|-
| 1"
| 25.4&nbsp;mm
| 9.6 × 12.8&nbsp;mm
| 16.0&nbsp;mm
| 16&nbsp;mm
|-
| [[Four Thirds system|Four Thirds]]<ref name = "Four Thirds">{{citation | url = http://www.four-thirds.org/en/about/standard.html | publisher = Four Thirds Consortium | title = The Four Thirds Standard | access-date = 2009-04-17 | year = 2008 | archive-url = https://web.archive.org/web/20090307060248/http://www.four-thirds.org/en/about/standard.html | archive-date = 2009-03-07 | url-status = dead }}</ref>
| 33.9&nbsp;mm
| 13 × 17.3&nbsp;mm<ref name = "Olympus">{{cite web | url = http://www.olympus-europa.com/consumer/dslr_7045.htm | archive-url=https://web.archive.org/web/20110927125844/http://www.olympus-europa.com/consumer/dslr_7045.htm | publisher = Olympus Europa | title = No more compromises: the Four Thirds standard | archive-date=2011-09-27 }}</ref>
| 21.63&nbsp;mm
| 22&nbsp;mm
|-
| 4/3"
| 33.9&nbsp;mm
| 13.5 × 18.0&nbsp;mm
| 22.5&nbsp;mm
| 23&nbsp;mm
|-
| APS-C
| 45.7&nbsp;mm
| 15.1 × 22.7&nbsp;mm
| 27.3&nbsp;mm
| 27&nbsp;mm
|-
| [[Nikon DX format|DX]]
| n/a
| 15.8 × 23.7&nbsp;mm
| 28.4&nbsp;mm
| 28&nbsp;mm
|-
| [[Full-frame digital SLR|FF]] (35&nbsp;mm film)
| n/a
| 24 × 36&nbsp;mm
| 43.3&nbsp;mm
|  50&nbsp;mm
|-
| (6 × 5&nbsp;cm)
| n/a
| 36.7 × 49.0&nbsp;mm
| 61.2&nbsp;mm
|
|}

===Cinema===
In [[cinematography]], a [[focal length]] roughly equivalent to twice the diagonal of the image projected within the [[camera]] is considered normal, since movies are typically viewed from a distance of about twice the screen diagonal.<ref>Anton Wilson, ''Anton Wilson's Cinema Workshop'', American Cinematographer, 2004 (Page 100) [https://books.google.com/books?id=18Ck5PZX_ZsC&dq=cinematography+normal-lens&pg=PA101 online].</ref>

{| class="wikitable"
|-
! Film format !! Image dimensions !! Image diagonal !! Normal lens focal length
|-
| [[8 mm film|Standard 8]]
| 3.7 × 4.9&nbsp;mm
| 6.11&nbsp;mm
| 12–15&nbsp;mm
|-
| [[8 mm film|Single-8]] (FUJI)
| 4.2 × 6.2&nbsp;mm
| 7.5&nbsp;mm
| 15–17&nbsp;mm
|-
| [[Super 8 mm film|Super-8]]
| 4.2 × 6.2&nbsp;mm
| 7.5&nbsp;mm
| 15–17&nbsp;mm
|-
| [[9.5 mm film|9.5&nbsp;mm]]
| 6.5 × 8.5&nbsp;mm
| 10.7&nbsp;mm
| 20&nbsp;mm
|-
| [[16 mm film|16&nbsp;mm]]
| 7.5 × 10.3&nbsp;mm
| 12.7&nbsp;mm
| 25&nbsp;mm
|-
| [[35mm movie film|35&nbsp;mm]]
| 18.0 × 24.0&nbsp;mm
| 30.0&nbsp;mm
| 60&nbsp;mm
|-
| [[35mm movie film|35&nbsp;mm]], sound
| 16.0 × 22.0&nbsp;mm
| 27.2&nbsp;mm
| 50&nbsp;mm
|-
| [[65 mm film|65&nbsp;mm]]
| 52.6 × 23.0&nbsp;mm
| 57.4&nbsp;mm
| 125&nbsp;mm
|-
|}