Meaning of f-number






The following texts are the property of their respective authors and we thank them for giving us the opportunity to share for free to students, teachers and users of the Web their texts will used only for illustrative educational and scientific purposes only.

All the information in our site are for educational uses.

The information of medicine and health contained in the site are of a general nature and purpose which is purely informative and for this reason may not replace in any case, the council of a doctor or a qualified entity legally to the profession.


Digital photography

Glossary of photography terms


Meaning and definition of f-number :


The number resulting when the focal length of a lens is divided by the diameter of the aperture. A sequence of f-numbers calibrates the aperture in regular steps (known as stops) between the minimum and maximum openings of the lens. The f-numbers generally follow a standard sequence, in such a way that the interval between one full stop and the next represents a halving or doubling in the image brightness. The f-numbers become progressively higher as the aperture is reduced to allow in less light, i.e. f/5.6, f/8, f/11, f/16, f/22... Theoretically, all lenses at the same f-number produce images of equal brightness. Also called f-stop or relative aperture.


For the term f-number may also exist other definitions and meanings, the meaning and definition indicated above are indicative not be used for medical and legal or special purposes.


Source :

Web site link of source :

Author : not indicated on the source document of the above text


If you are the author of the text above and you not agree to share your knowledge for teaching, research, scholarship (for fair use as indicated in the United States copyrigh low) please send us an e-mail and we will remove your text quickly.


Fair use is a limitation and exception to the exclusive right granted by copyright law to the author of a creative work. In United States copyright law, fair use is a doctrine that permits limited use of copyrighted material without acquiring permission from the rights holders. Examples of fair use include commentary, search engines, criticism, news reporting, research, teaching, library archiving and scholarship. It provides for the legal, unlicensed citation or incorporation of copyrighted material in another author's work under a four-factor balancing test. (source:


Google key word : f-number


Glossary of photography terms




If you want to quickly find the pages about a particular topic as f-number use the following search engine:



Meaning and definition of f-number

What does it mean f-number explanation


Please visit our home page Terms of service and privacy page




Meaning and definition of f-number