The shutter is the device that allows light to enter the camera and then shut it off again after a predetermined length of time. The earliest cameras simply used a lens cap that the photographer removed, then replaced - such was the speed of the embryonic photo sensitive materials, that the time between these two events could be measured with a watch.

As the speed of photographic emulsions increased in company with improvements processing the images, the shutter was developed into a refined mechanical device capable of accurately allowing exposures of fractions of a second. Today it is commonplace to find cameras with shutter speeds of 1/1000th sec. or faster.

A variety of different shutters evolved, some endured - others vanished long ago. Here are the major types.

Roller blind shutters
Diaphragm shutters (sometimes called leaf shutters)
Rotary shutters

These broad types of shutter can be located in the camera at one of two positions, either the focal plane (just in front of where the film passes) or at the lens. In the case of the latter the shutter may be located in front, between or behind the lens. A significant proportion of cameras up to the 1960s had shutter mechanisms fitted from specialist manufacturers, the camera maker concentrating on the light tight box. The exceptions to this were the very cheap rotary blade shutters fitted to box cameras and the built in focal plane type shutters fitted to the early, and subsequent, Single Lens Reflex and Rangefinder cameras. In the following pages the earliest common incarnation of each of the shutter types will be discussed followed by the developments that led on from it.