Auxiliary light and light speed photography

Aperture represents the size of the effective entrance hole of the camera lens, which is expressed by F value. The larger the value is, the smaller the entrance hole is, and the proportional sequence with root number 2 increases. Because the aperture value is defined to be inversely proportional to the diameter of the hole, every 2 times (1.4 times) increase in the root number value means that the area of the hole is reduced by half. Aperture setting values are generally as follows: F32, F22, F 16, f1,F8, F5.6, F4, F2.8, F 1.0. Of course, now the camera is divided more finely, with half or one third of the aperture value increasing step by step, so in addition, the larger the aperture (the smaller the value), the less profound the photos taken. That is, the background is blurred and the theme is prominent, which is why so many enthusiasts spend huge sums of money to buy large aperture lenses.

The shutter represents the exposure time of the photosensitive element. Under normal circumstances, it is expressed by the reciprocal of exposure time, and it is increased by an equal proportion sequence of 2. The larger the value, the shorter the exposure time, such as 1, which means 1 sec, 2 means 0.5 sec, and the shutter speed continues to increase at full speed, 4,8,16,30,60. Of course, there is also a one-third increase. The faster the shutter is, the easier it is to cure, so when shooting dynamic things, it is generally necessary to increase the shutter speed, that is, to increase the numerical value.

Sensitivity refers to the sensitivity of cmos photosensitive elements to light, which is increased by 2 times. The higher the sensitivity, the more sensitive to light. The overall improvement is generally as follows: 100, 200, 400, 800, 1600, 3200, 6400 ... However, when the sensitivity to effective light is improved, the photosensitive element will also be sensitive to some dark current, and there will be noise on the picture, so the picture with high sensitivity will become rougher and less delicate. In the case of dark light, the iso should be properly improved for normal exposure. However, if the light permits, iso should be as low as possible to ensure the image quality.

Specific to the operation, I generally use the aperture priority mode: the so-called aperture priority means that when setting the sensitivity, users can customize the aperture size. Then the camera automatically calculates the required shutter speed according to the shot scene and automatically sets the shutter, just like the faucet mentioned above. After you set the switch size of the faucet, the faucet will know the required time according to the volume of the bucket, and then automatically turn off the faucet when it is time (equivalent to the light on the scene photographed by the camera).

If you want to highlight the blurred background of the subject, you should raise the aperture (lower the value). This is very practical when shooting beautiful women. If you want to make the whole scene clear, you should turn down the aperture. For example, shooting scenery generally requires the clarity of the foreground and background to be within an acceptable range.

I don't know. You got it?