How to set the aperture, shutter and sensitivity of the camera

1 First of all, it should be understood that aperture, shutter and sensitivity are all factors (parameters) that affect the normal exposure of photos. In full manual mode, these three parameters need to be set correctly and mutually restricted in order to get normal exposure photos. Let's take a look at the influence of the change of the third parameter on the exposure when one or two parameters are fixed:

(1) Aperture: expressed by numerical value, such as f=5.6. The aperture values on the camera are 1.8, 4, 5.6, ..., 20, etc. Different cameras can be assigned different levels. But there is such a rule: the smaller the value, the larger the aperture and the more light entering; The larger the numerical value, the smaller the aperture and the less the amount of light entering. Therefore, the bigger the aperture (the smaller the value), the brighter the photo will be.

(2) Shutter: This is easy to understand. It controls the exposure time of this photo. The camera shutter speed is usually door B, 1 sec,1/sec, 1/4 sec, ...,1125, ..., 1/2000 sec. Door B is to press the shutter button and control the exposure time at will until the shutter button is released. Everything else is easy to understand. We can easily understand that the longer the exposure time, the brighter the photo. In the past, in the traditional photography era, people with low skills usually used a camera to shoot at a speed of1125 seconds (the reason will be explained below). Nowadays, in the era of national photography, most people can take pictures in a wider speed range.

(3) Sensitivity: If you want to know what sensitivity is. First of all, we should understand the concept of sensitivity in the traditional photography era. The change of sensitivity in the traditional photography era is not set by digital cameras now, but depends on the sensitivity of the film used. The camera can only change the aperture and shutter. At that time, the film was divided into different photosensitive speeds (identified by different ISO values), such as 50 degrees, 100 degrees, 200 degrees, 400,800 degrees,1600,3200 and so on. At that time, people used 100 degrees most often.

The meaning of traditional film ISO value: the greater the value, the more sensitive the film is to light and the faster the exposure speed. Under the same exposure (that is, the shutter and aperture are fixed), the greater the ISO value, the more adequate the film exposure. Therefore, when the shutter and aperture are fixed, the ISO is too large, which will lead to overexposure of the film.

People call the film with high ISO value high-speed film. There are two meanings: one is that film can quickly perceive light, and the other is that people can shoot with higher shutter speed when shooting with this film. The reason will be explained below).

After understanding the sensitivity of traditional film, let's talk about the sensitivity of digital cameras. It can also control the sensitivity of digital photography as in the traditional era. Personally, I think the concept of sensitivity of digital camera is transplanted from the sensitivity of film. Digital cameras are purely electronic products. Through electronic operation control, photographers can find the feeling of traditional cameras on digital cameras. Novices who know nothing about traditional photos are often confused about the concept of sensitivity.

Therefore, in a digital camera, when the shutter and aperture are fixed, the larger the ISO, the brighter the photo.

2. After knowing the meanings of these three parameters, it is not difficult for us to understand that these three parameters are closely related when taking pictures. Let's talk about their relationship from the perspective of getting proper exposure:

(1) When the sensitivity is fixed, the larger the aperture, the smaller the shutter speed.

(2) When the aperture is fixed, the greater the sensitivity, the smaller (faster) the shutter speed.

(3) When the shutter speed is fixed, the larger the aperture, the smaller the sensitivity.

It seems that your question has not been answered here, but understanding the above content is the basis to solve the problem.

4. If it is purely to get the right exposure, everyone must know what to do. But in fact, if you want to take a satisfactory photo, you must also know the following points:

(1) shutter speed: If you don't have a tripod and shoot with a hand-held camera, the lower (slower) shutter speed will easily lead to jitter and blur the photo. In the traditional photography era, the shutter speed should be above 1/60 seconds (faster) when holding a camera. People with high level can use 115 seconds or even1second.

In addition: even if you have time to keep the camera absolutely stable, the subject is moving rapidly, and the photos you take at a low shutter speed are definitely not clear. At this time, it is necessary to increase the shutter speed.

Also, when using a flash, you may not be able to use a higher shutter speed, and you need to control it below a certain value (that is, a slower speed). This value may be different for different digital cameras. This speed is called flash synchronization speed.

Therefore, the appropriate shutter speed depends on the above factors.

(2) Aperture: The size of the aperture not only affects the exposure, but also affects the depth of field. The depth of field can be understood as follows: the distance in a photo, the relatively clear range. The larger the aperture, the smaller the depth of field, and the smaller the aperture, the greater the depth of field. Of course, the factor that affects the depth of field is the focal length of the lens. When the focal length is larger, the influence of aperture on depth of field will be more obvious. If you want to take a picture with a blurred background, you'd better turn the aperture to the maximum.

(3) Sensitivity: The influence of sensitivity on exposure will cause (or help) the photographer to change the shutter speed. For example, when you want to shoot at a higher speed, you can set the sensitivity to high.

However, sensitivity has an impact on the quality of photos: higher sensitivity will add more noise to photos, and particles will appear on the original flat and soft plane. The lower the sensitivity, the softer and more delicate the photo will be. Therefore, when shooting people, it is best to use a low ISO value to make people's faces and skin look good. Generally speaking, below 400 is good. If conditions permit, it is recommended to use the sensitivity of 100.

In the traditional movie era, at that time, you couldn't see the shooting effect. Photographers always shoot by experience. Better cameras have automatic metering, but photographers are usually more willing to trust their own experience than rely on automatic metering equipment. At that time, there was such an experience about exposure:

At that time, ISO= 100, sunny (9 am; 00-17: 00 p.m.) Under outdoor shadows, if the aperture f=5.6 and the shutter is1125 seconds, correct exposure can be obtained.

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At night, indoors, under bright fluorescent lamp, ISO= 100, aperture f=5.6, shutter 1 s, you can get correct exposure.

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A friend said that the shutter speed of 1 sec is too long. Once unstable, isn't it blurred? Why not use a larger ISO film? I want to tell you that at that time, the market was full of ISO= 100 degree films. You can't buy high-speed movies in third-and fourth-tier cities.

6. Now the digital camera can check the shooting effect at any time, which also provides convenient conditions for everyone to adjust the shooting parameters in time. But many people have no idea about aperture, shutter and sensitivity because they don't use manual function. So these people inadvertently practiced a hard skill: holding a camera and shooting at a very low shutter speed. Why do you say that? In fully automatic mode, the camera will automatically set these three parameters. When the light is dim, the camera will set the shutter speed to 1/8 seconds or slower in addition to setting the ISO very high. At first, the photos taken by these people were blurred because of their unstable hands. After a long time, their efforts to stabilize the camera improved.

7. After understanding the above contents, you will find it very useful to take high-quality photos with a SLR camera, and it is also necessary to buy a tripod.