Shutter button

In photography the shutter-release button (sometimes just shutter release or shutter button) is a push-button found on many cameras, used to take a picture.^[1] When pressed, the shutter of the camera is "released", so that it opens to capture a picture, and then closes, allowing an exposure time as determined by the shutter speed setting (which may be automatic). Some cameras also utilize an electronic shutter, as opposed to a mechanical shutter.

The shutter-release button is one of the most basic features of a handheld camera. Camera phones that lack a physical button for this purpose use a virtual button on the virtual keyboard.

The term "release" comes from old mechanical shutters that were "cocked" or "tensioned" by one lever, and then "released" by another.^[2] In modern-day photography, this notion is less meaningful, so is gradually falling from use.

References

1. ↑ David D. Busch (2006). Digital Photography All-in-One Desk Reference for Dummies. For Dummies. p. 260. ISBN 978-0-470-03743-0. 
2. ↑ Peter G. Dorrell (1994). Photography in Archaeology and Conservation. Cambridge University Press. p. 42. ISBN 978-0-521-45554-1.