In photography, a central shutter is a type of camera shutter, so called because it is situated between the lens and the focal plane. In many cases it is contained within the lens body itself, at the convergent image point.

For this reason many cameras with a central shutter and interchangable lenses require that each lens for that camera has a shutter built into it. Note that this would also require the lenses to be changed in complete darkness, or have a secondary shutter or darkslide that can be operated to prevent film exposure occuring.

The most common type of central shutter is the metal leaf shutter (Fig 1,2), where a single metal leaf covers an aperture to prevent exposure, and is made to briefly uncover the aperture by means of a spring and lever system to make the exposure. The time of exposure is controlled by a timing mechanism on shutters with a variable shutter speed.

Simple leaf shutter

1. Shutter plate
2. Shutter aperture covered by leaf shutter.
3. Shutter aperture during exposure.
4. Leaf blade
5. Catch mechanism
6. Butterfuly spring, lever operated, self resetting

Simple leaf shutters often only have one shutter speed and are used on disposable cameras and most point-and-shoot cameras. The more complex types have variable shutter speeds and are used on most rangefinder, twin lens reflex, and large format cameras.

The main advantages of the central shutter are:

Relatively simple construction is possible.
Many cheap versions have no requirement for a cocking mechanism or variable shutter speeds which further simplifies construction.
Cheaper to produce even the complex versions than a focal plane shutter
Flash synchronization is possible at all speeds.
Small size is acheived by placing the shutter at the focal convergent point either inside the lens or inside the camera body.
Many versions have no connection between the cocking mechanism and the film advance mechanism, making multiple exposures possible.

Some of the disadvantages of the central shutter are:

Each lens in an interchangable system has to have a shutter built into it.
Shutter speeds are limited to how fast the leaf blade can be made to move; normally 500th or 250th of a second.
Many versions have no connection between the cocking mechanism and the film advance mechanism, making accidental multiple exposures a common problem.
On medium format and small format systems a separate viewfinder, rangefinder, or twin lens reflex system has to be provided for focusing and composition.