What is a curtain shutter for a more formal explanation

As the name suggests, the curtain shutter means that the shutter is mounted behind the lens and is close to the negative, because the front of the negative is covered by a black curtain or steel sheet, and the film will not run out, so this kind of camera can change the lens, which is more convenient. Higher-end cameras use this shutter, the speed is the same as the shutter between lenses, the index is engraved on the outer ring of the lens, and there is a bulb and bulb, both representing 1 n seconds.

It is mounted between the lens and the film near the focal plane, also known as the focal plane shutter. This shutter is transported according to the curtain. The advantage of curtain shutters is that they are faster than the inter-lens shutter, up to 1 1000 to 1 2000 seconds, and some longitudinal metal shutters can reach 1 4000 to 1 8000 seconds.

The curtain shutter is like the curtain of the stage, consisting of two curtains on the left and right, and in order to better block the entry of light, there must be an overlapping part of the curtain. The overlapping part of the shutter is not like the stage curtain in the middle, but on one side.

Curtain shutter principle: one side of the ** window is A, and the other side is B.

**The overlapping part of the first two curtains is in A, the first curtain is opened from A to B, revealing the ** mouth, at an interval of time, the second curtain coincides with the first curtain after A to B, and completes a complete **, during which the light through the window is **amount, and the whole process is **time (full opening time + opening process time of the two curtains).

The earliest curtain shutter is really called the curtain shutter, which is made of black cloth, and increases its strength and wear resistance through gluing and other processes, and it is also a horizontal movement, and later there is an up and down movement, but because the life of the curtain shutter is shorter, the durability is poor, and the speed will not be very high, and then there are steel shutters, carbon fiber shutters and composite shutters, and the durability and speed have made a qualitative leap.

In addition to up and down, left and right, and oblique, there are also oblique movements.

In addition to the curtain shutter, there is also a mirror shutter. It can be understood as a completely closed aperture.

The curtain shutter is composed of a front curtain and a rear curtain, the front curtain runs from one side to the other side is the process of opening the shutter, and the rear curtain runs from one side to the other side is the process of closing the shutter.

The curtain shutter is generally set on a single-lens reflex camera, and the curtain shutter is close to the point plane of the focal hall, so it is also called the focal plane shutter.

In order to achieve accurate photosensitive materials in different light environments, the camera can adjust the shutter speed of the camera in addition to the aperture size adjustment to achieve the purpose of accurate vertical smile.

If the shutter speed of the camera is set at 1 2 seconds, the timing will start at the start of the current curtain operation, and the rear curtain will start running at 1 2 seconds**. In other words, the time between the front and rear curtains is the set shutter opening time.

The early curtain shutter was made of opaque curtains, also known as curtain shutters, with spring scrolls to drive the curtain shutter to run, the shutter curtain ran slowly from the beginning to the end, and the time from the shutter curtain to the end of the operation was about 1 60 seconds, so it was difficult to achieve a shutter opening time shorter than 1 1000 seconds.

Assuming that the camera's shutter curtain runs from one side to the other for 1 60 seconds, we set the camera's shutter opening time to 1 125 seconds. When the front curtain runs halfway, 1 125 seconds is up, the rear curtain starts to run, at this time the front curtain and the rear curtain keep one-half of the gap of the focal plane to continue to run at the same time, when the front curtain runs in place and stops running, the rear curtain has also reached the position of one-half, and the rear curtain continues to run until the shutter is completely closed, completing the ** process of 1 125 seconds. In the same way, if we set the shutter opening time of 1 1000 seconds, then, the front curtain only runs 1 16 in 1 1000 seconds, and the rear curtain starts to run at this time, and at this time, there is only a very small gap of 1 16 focal plane length between the front curtain and the rear curtain to sweep through the focal plane to complete the ** process of 1 1000 seconds.

For a 135 film camera, sweeping the gap between the focal plane 1 and 16 is.

The camera's shutter curtain runs slowly, which has great restrictions on synchro flash, and the shutter opening time of synchro flash can only be selected for synchro flash photography when the shutter curtain is greater than or equal to the shutter curtain running time, otherwise the synchro flash will not be synchronized.

The curtain shutter is composed of a front curtain and a rear curtain, the front curtain runs from one side to the other side is the process of opening the shutter, and the rear curtain runs from one side to the other side is the process of closing the shutter.

With the development of technology, the original curtain shutter has been replaced by a steel shutter with multiple combinations and overlaps, and the running speed of the curtain shutter has been increased. Since the focal plane is 35 mm horizontally and 24 mm longitudinally, the horizontal shutter was later changed to a vertical shutter, which shortens the distance of the shutter and further shortens the running time.

As mentioned above, the "steel shutter" is not necessarily made of "steel sheet", as long as it is a strong and rigid material, including the shutter of plastic sheet, it is also called "steel shutter".

Since then, some cameras have been made of very tough and thin titanium shutter curtains, which run much faster due to their thin and light texture. In order to solve this problem, engineers made the titanium alloy sheet into a honeycomb shape to impose its strong performance to make the shutter curtain more perfect. The shortest shutter time can be 1,8000 seconds.

In modern digital cameras, the area of the photosensitive material CCD is smaller than that of the original film, and the further development of science and technology has further shortened the shutter opening time.

Definition of technical terms.

Chinese name: curtain shutter.

Definition: It consists of two opaque curtains (one of which has a gap) located on the focal plane, and the movement of the curtain controls the time.

Applied Disciplines: Surveying and Mapping (first-level discipline); Photogrammetry and Remote Sensing (Secondary Discipline) The curtain shutter is generally set on a single-lens reflex camera, and the curtain shutter is close to the focal plane, so it is also called the focal plane shutter.

In order to achieve accurate photosensitive materials in different light environments**, the camera can adjust the shutter speed of the camera in addition to the aperture size adjustment to achieve the purpose of accuracy**. The "shutter speed" mentioned here is more precisely the "shutter opening time", for example, the shutter opening time is 1 second or 1 60 seconds, 1 500 seconds, 1 8000 seconds, and so on. In the earlier data, the "shutter opening time" was called "shutter speed", or perhaps it was a mistake when translating foreign language materials into Chinese, so most people called "shutter opening time" "shutter speed".

If we set the camera's shutter speed at 1 2 seconds, then the clock will start at the start of the front curtain and the end of the curtain at 1 2 seconds. In other words, the time between the front and rear curtains is the shutter opening time we set.