"Thinking Degree" of Digital Camera —— Shutter

First of all, welcome to the photography class of Ai Xueqing Youth Club. Today we are going to have the fifth lesson of portrait photography: learn to shutter, want to take pictures quickly? Want to take a picture as slow as a snail? Want to take a unique and powerful photo? The correct use of the shutter can satisfy you. The following is the relevant information I have compiled. Come and study together.

shutter

Shutter plays an important role in various devices of camera. The shutter is like a faucet. When it is open, light can reach the photosensitive film, and when it is closed, light cannot reach the photosensitive film. In other words, the shutter controls how long the light stays on the photosensitive film. When shooting a moving object, mastering the shutter speed is for the photographer to grasp the motion and make the moving object form a clear image on the film.

1. Marking of shutter speed

Modern cameras have multi-stage shutter speeds, as slow as a few seconds and as fast as a few thousandths of a second. The greater the change of camera shutter speed, the better, especially at high speed. The highest shutter speed of many modern high-end cameras has reached 1/8000 seconds.

The speed of the shutter is in seconds. Under the condition of constant aperture, the longer the shutter is opened, the more exposure the film receives; The shorter the opening time, the less exposure the film receives.

Common shutter speed marks on cameras are 1, 2, 4, 8, 15, 30, 60, 125, 250, 500, 1000, etc. These numbers all represent the countdown seconds of the actual shutter speed. For example, 30 indicates that the actual shutter speed is 1/30 seconds.

Under the condition of constant aperture, the exposure of two adjacent shutter speeds is twice as different. For example, the exposure of 1/60 seconds is twice that of1125 seconds; The exposure of 1/500 seconds is half that of 1/250 seconds.

On some cameras, the other side of the 1 sec mark is marked with 2, 4, 8, 15, 30, etc. These numbers indicate how many seconds the actual shutter speed is. For example, 8 indicates that the actual shutter speed is 8 seconds.

"B" or "T" is also a common camera shutter speed sign, commonly known as slow door. The operation modes of "B" door and "T" door are different: B door presses the shutter button and the shutter opens; Release the shutter button and the shutter will close. T door is to press the shutter button and the shutter opens; To close the shutter, press the shutter button again.

A shutter and p shutter are used for automatic exposure. A shutter means automatic shutter selection, and P shutter means program automatic, that is, the combination of shutter and aperture is automatically selected according to program settings.

In addition, for the mechanical shutter, the shutter can not be adjusted between two shutter speeds, but only on the mark of the shutter speed, otherwise the mechanical device of the shutter will be damaged.

2. The role of the shutter

From the definition of shutter, the basic function of shutter is to control the light entering time. The second function of the shutter that affects the imaging definition is the negligible function of the combination of shutter speed and aperture. For digital cameras with anti-shake function when the shutter is opened, in order to ensure the clarity of the image, the shutter time should not be shorter than the reciprocal of the focal length of the lens used. In addition, when the camera is stable (that is, it is fixed on a tripod or the anti-shake function is turned on), the speed is appropriately extended, and the extraordinary dynamic effect of dynamic and static contrast and combination of reality and reality is created through the contrast between the virtual and real characters in the picture.

3. About shutter lag and shutter delay

Unfortunately, the opening time of the shutter and the pressing time of the shutter are often not guaranteed to be the same. When the camera does not use the focus lock function and ensures that it is in the auto-focus working state, the time from pressing the shutter release button to starting exposure is called shutter lag. At the same time, when the shutter is pressed, the time required for the camera to automatically focus, measure light, calculate exposure, select an appropriate exposure combination, calculate and store data is called shutter delay. The shutter delay time and shutter delay time of different cameras are also different. A single-lens reflex camera needs to complete a series of preparatory work such as raising the mirror and reducing the aperture after pressing the shutter button, so the shutter lag time is long. Paraxial cameras have no mirrors, and most of them use program shutters, so the time lag is short.

The shutter lag time is too long, which is not conducive to the instantaneous capture of moving people. When shooting portraits in low light, the fast focusing speed is easy to cause virtual focus. The shutter start time of professional digital SLR cameras is almost synchronized. For example, the shutter lag of Canon 5DMark3 is only 59 milliseconds, and the shutter delay is 0. 16 seconds.

summary

The photographic lens focuses the light projected by the photographed scene on the plane of the photosensitive material, and the function of the shutter is to control the exposure time of the optical image. Shutter plays an important role in various devices of camera. It determines the exposure time of photosensitive materials and affects the dynamic curing of the camera to the subject and the stability of the camera itself. Moreover, due to its unique type and structural differences, it also affects the scope of application and environment of the camera to varying degrees.

Static beauty, dynamic beauty, let the trend of sports help you and me, and let the shocking beauty shine. Learn the little knowledge of shutter to add color to our picture. That's all for today's sharing. I hope my sharing can help you. You are also welcome to comment on the message. Open it if you like, and don't get lost. See you next time.