Editing Depth of field (section)

===Effect of lens aperture===
For a given subject framing and camera position, the {{abbr|DOF|depth of field}} is controlled by the lens aperture diameter, which is usually specified as the [[f-number]] (the ratio of lens focal length to aperture diameter). Reducing the aperture diameter (increasing the {{nowrap|f-number}}) increases the {{abbr|DOF|depth of field}} because only the light travelling at shallower angles passes through the aperture so only cones of rays with shallower angles reach the image plane. In other words, the [[circle of confusion|circles of confusion]] are reduced or increasing the {{abbr|DOF|depth of field}}.<ref>{{Cite web| url = http://physicssoup.wordpress.com/2012/05/18/why-does-a-small-aperture-increase-depth-of-field/| title = Why Does a Small Aperture Increase Depth of Field?| date = 18 May 2012}}{{Self-published source|date=February 2024}}</ref>

For a given size of the subject's image in the focal plane, the same {{nowrap|f-number}} on any focal length lens will give the same depth of field.<ref>{{Cite web |date= 13 January 2009 |last= Reichmann |first= Michael |title= DOF2 |url= https://luminous-landscape.com/dof2// |website= Luminous Landscape}}</ref> This is evident from the above {{abbr|DOF|depth of field}} equation by noting that the ratio {{math|''u''/''f''}} is constant for constant image size. For example, if the focal length is doubled, the subject distance is also doubled to keep the subject image size the same. This observation contrasts with the common notion that "focal length is twice as important to defocus as f/stop",<ref>{{Cite web| url = https://www.kenrockwell.com/sony/lenses/50mm-f12.htm| title = Ken Rockwell}}{{Self-published source|date=February 2024}}</ref> which applies to a constant subject distance, as opposed to constant image size.

Motion pictures make limited use of aperture control; to produce a consistent image quality from shot to shot, cinematographers usually choose a single aperture setting for interiors (e.g., scenes inside a building) and another for exteriors (e.g., scenes in an area outside a building), and adjust exposure through the use of camera filters or light levels. Aperture settings are adjusted more frequently in still photography, where variations in depth of field are used to produce a variety of special effects.

{{Multiple image
| align = center
| direction = 
| width = 250
| footer = Depth of field for different values of aperture using 50{{nbsp}}mm objective lens and full-frame DSLR camera. Focus point is on the first blocks column.<ref name="photoskop">{{Cite web |url=http://www.photoskop.com/player.html?l=all&ch=3&sec=0 |title=photoskop: Interactive Photography Lessons |date=April 25, 2015}}</ref>{{Better source needed|reason= Citation is to an Adobe Flash animation, which is dead.|date=February 2024}}
| image1 = Dof blocks f1_4.jpg
| caption1 = Aperture{{nbsp}}= {{f/|1.4}}. {{abbr|DOF|depth of field}}{{nbsp}}= 0.8{{nbsp}}cm
| image2 = Dof blocks f4_0.jpg
| caption2 = Aperture{{nbsp}}= {{f/|4.0}}. {{abbr|DOF|depth of field}}{{nbsp}}= 2.2{{nbsp}}cm
| image3 = Dof blocks f22.jpg
| caption3 = Aperture{{nbsp}}= {{f/|22}}. {{abbr|DOF|depth of field}}{{nbsp}}= 12.4{{nbsp}}cm
}}