المغلاق أو الغالق - ٢ - طريقة عمل آلة التصوير .. كتاب التصوير الضوئي

Shutter or Shutter - 2 - How the Camera Works .. Book of Photography

Flash timing or flashing in relation to the shutter speed. When using a flash with a burning shutter, the entire distance of the film must be exposed when the flash is fired. The speed must be chosen so that the second curtain moves after the first curtain has finished its travel (as is the case with instant machines). By the time the first curtain reaches the other end, the flash contact occurs before the second curtain has gone. The timing speeds for electronic flashes are usually 60/1 second (or longer) for a burning shutter with curtains and 125/1 second (or longer) for a burning shutter with metal plates that operate vertically. In the case of a central shutter (placed in the lens) the entire film remains exposed at the same time and the flash can be stopped at all speeds. However, the timings are noted so that the flash reaches its maximum power exactly when the plates are completely apart.

This is what you get when you use a flash and the shutter is not set to the right speed: the flash is triggered when only part of the film is exposed by the first curtain.

Shutter speeds: With a burning shutter, fast speeds are achieved by adjusting the width of the slit. Both curtains then operate at the same speed so that the width of the slit remains constant. The time taken to shoot the picture gets shorter as the slit narrows.

At the end of the process, each film is equally exposed.

Central shutter

The central shutter (under) is usually placed in the lens near the pupil (above). There is a complex mechanism that opens and closes a series of thin plates starting from the center (drawings to the right) between
1/30 and 1/500 seconds. The spring tension determines the speed.

As for slow speeds of 1/15 to 1 second, the shutter is equipped with a balance. In addition to these speeds, most shutters have signals (B) or (T). In the (B) signal, the shutter remains open as long as we press the button, and in the (T) signal, the shutter opens until another movement is made to close it. With this type of shutter, we usually feed the springs whose energy moves the plates. In some machines, the film advance process feeds the shutter.

Expressing movement by choosing the speed

A high shutter speed (freezes) the movement of a moving subject and gives a completely clear image. The slower the shutter speed, the more shaky the images of the moving subject. The clarity The image of a moving subject depends on its distance, speed, shutter speed, the angle of its path relative to the machine, and the angle of capture of this subject. A faster shutter speed is required to stabilize a subject moving parallel to it than the speed required for an oblique path relative to the optical axis.

A car moving on a curve appears to vibrate at a speed of 1/60 sec.

A car moving parallel to the film vibrates at a speed of 1/125 sec.

At a speed of 1/125 sec, the image appears less vibrating.

At a speed of 1/250 sec, the image appears less vibrating.

At a speed of 1/250 sec, the resulting image appears clear.

Stabilization Parallel movement of the machine is necessary.

Setting a speed of 1/500 sec or more is available.