Introduction to Photography

1. Three elements of photography: aperture, ISO and shutter speed (two degrees per turn)

1. The aperture

The aperture is the device in the lens that adjusts the size of the light hole. (I.e., a window; the bigger the window, the more light gets in and the brighter the picture)

Common aperture values are as follows: F1, F1.4, F2, F2.8, F4, F5.6, F8, F11, F16, F22, F32, F44, F64. The amount of incoming light between adjacent apertures of each two blocks is one time different. For example, adjust the aperture from F4 to F2.8, the amount of light will be doubled; From F2.8 to F2 double again. The larger the number, the smaller the aperture.

① Large aperture (F /1.4, F /1.8, F /2.8, etc.), suitable for insufficient light line. Effect: Shallow depth of field; Increase the exposure time (shutter speed is slow), the photo becomes brighter; Solidification time (fast moving object).

② Small aperture (F /11, F /16, F /22, etc.), suitable for sufficient light line. Effect: Depth of field deepens; Capture time (running water, train track); Make the spot scatter, the light.

Larger aperture = Smaller number = Background Blur/Depth = Portrait (smaller aperture means smaller clear area)

Small aperture = Large number = clear background/Depth = scenery (the larger the aperture, the larger the clear area)

The lens produces the best image at a medium aperture, and the aperture at which it produces the best image is the optimum aperture.

A. Depth of field: the distance that can be clearly photographed.

Small depth of field, clear foreground, blurred background; The depth of field is large, the foreground is clear and the background is equally clear.

B. Three factors affect the depth of field:

The larger the aperture, the shallower the depth of field.

The longer the focal length of the lens, the shallower the depth of field;

The closer the camera is to the subject, the shallower the depth of field.

Aperture serves three purposes:

A, control the amount of light, which directly affects whether the picture can be correctly exposed, is the key to the success of shooting;

B. Control the depth of field. The smaller the aperture, the larger the depth of field. Although both focal length and distance affect the depth of field, changes in focal length and the distance of the subject also affect the composition. If the composition is determined, the only weapon we have to control the depth of field is the aperture.

C, aperture affects the sharpness of the picture, any lens is at medium aperture when the image is the best (the picture is the clearest), at the maximum aperture and minimum aperture when the resolution is poor.

One of the most important concepts in photography: aperture first. Aperture priority is a manual definition of the aperture size, the camera based on this aperture value to determine the correct exposure shutter speed.

2. Sensitivity ISO

That is, the sensitivity of CMOS to light.

① Low sensitivity is below ISO50

In this section you can get extremely smooth and detailed photos. As long as you can get a clear picture, use a low sensitivity as much as possible. For example, as long as you can keep the depth of field, it is better to have a higher aperture than a higher sensitivity.

In this section you can get extremely smooth and detailed photos. As long as you can get a clear picture, use a low sensitivity as much as possible. For example, as long as you can keep the depth of field, it is better to have a higher aperture than a higher sensitivity.

② ISO100-200 belongs to the medium sensitivity

In this section, you need to think carefully about what this photo is for and how big it should be. If you can accept noise, medium sensitivity reduces the difficulty of shooting with a handheld camera, improves the safety factor of shooting in low light conditions, and increases the success rate.

ISO400 above is high sensitivity

Sensitivity affects photography in two ways. The first is speed. Higher sensitivity leads to faster shutter speeds. The second is the picture quality, the lower the sensitivity brings more delicate imaging quality, and the high sensitivity of the picture quality is relatively large noise.

The higher the ISO value is, the faster the shutter speed can be provided in the same light source environment, which can effectively avoid the occurrence of false hand shaking.

Low ISO provides three major benefits for image shooting: high picture quality, low noise, and slow shutter speeds. Eg. The effect of low sensitivity is to reduce the shutter speed and create a different image flavor. For example, thin water, such as a waterfall, may require less than 1/2 second of shutter time in exchange for dynamic water flow. If in sunny outdoor, can also open the aperture wide (F2.8), reduce the ISO to ensure that the shutter speed within the fuseage limit range (1/4000 second or 1/8000 second), to reduce the chance of overexposure, to achieve a more soft and charming depth of field effect.

In the part of the night scene, it is mainly used in the need to condense the moment of the situation, by the way of high ISO large aperture frozen in front of the beautiful scenery, such as the mountain starry galaxy, night folk festival, hand-held city night scene and so on, are high ISO can control the theme scope.

The shutter speed

Shutter: The shutter is the device in a camera that controls the exposure time.

Speed is inversely proportional to exposure time: fast speed, short exposure time

When the shutter speed is high, the moment of high-speed motion is frozen; When the shutter speed is slow, a moving process is frozen (e.g. traffic, water becomes a dreamy band, i.e., "paste").

Safe shutter speed: The easiest way to take a hands-free photo is to have a fast shutter speed, which can lead to underexposure. So after continuous shooting, photographers came up with a theory of the slowest shutter value without shaking hands, known as the "safety shutter." Traditionally, the simple and general definition of a safe shutter is that the shutter value is no slower than 1/ focal length of the lens. Eg. If you use 50mm and the shutter value is 1/50, you can take a picture without shaking hands.