What Does shutter Mean
A shutter is defined as that which allows shutter . This verb (shutter), meanwhile, refers to blocking or covering a channel or a hole through the application or introduction of some element.
In the field of photography , the shutter is the mechanical device that, in a photographic camera, is responsible for controlling how long a film or sensor is exposed to light . We can distinguish three kinds of shutter: the simple blade , the central (also called lamella ) and the focal plane (or curtain ).
The simple leaf shutter is considered primitive, since its design is basic: it consists of a minimum of one pivoting metal sheet that in its normal state does not allow light to pass through the objective and reach the film; When the opening of this type of shutter is activated, the blades move so that the objective lens remains uncovered for as long as the exposure requires (period of time in which light can penetrate), until it is finally closed again.
In the design of the central shutter, we find a series of blades whose opening is radial , something similar to what happens with the diaphragm, another of the essential devices of the camera as it allows us to regulate the amount of light that enters. in her. This type of shutter is used on large format lenses, twin lens reflexes, and also certain medium format lenses.
Generally, the center shutter is on the lens and has the advantage of being able to synchronize with the flash regardless of the speed of the flash; its disadvantage, on the other hand, is that it cannot operate at an exposure speed greater than one five hundredth of a second, that is, one second divided into five hundred.
The focal plane shutter can be found in any single lens reflex camera, those that use a single lens for focus and image display. It is located in front of the light-sensitive device and, in almost all cases, it consists of two blinds whose movement occurs in the same direction: one for closing and the other for opening.
The operation of the focal plane shutter can be explained as follows: when we press the shutter button, a curtain descends and thus starts the exposure ; later, when the exposure time that we have indicated expires, another curtain moves to close the window through which the light has entered the film. Compared to the center shutter, the focal plane shutter is not as easy to sync with the flash; This occurs because at high speeds the closing of the second curtain can overlap with the opening of the first, generating an unwanted light sweep.
The shutter speed is the length of time the shutter remains open. Expressed in seconds and fractions, it allows control of the light that comes into contact with the photosensitive element.
In a general sense, it can be said that when the shutter is opened for a very short time, a small amount of light reaches the film or the sensor and the movement is slowed or frozen . On the other hand, if the shutter is left open for a long time, more light passes through and shaky images are captured.
When the shutter is open for a long time, and therefore there is a long exposure time, it is best to use a tripod to take the picture. Otherwise, the pulse vibration tends to make the photo lose sharpness due to shaking.