How to determine and select the adjustment level of aperture, speed and sensitivity of SLR camera?

When a SLR camera completes shooting, the choice of aperture, speed and sensitivity are the three “cornerstones” to ensure accurate or satisfactory exposure in one shot. The elimination and other advantages of the three are mutually matched to realize the exposure requirements of “negative film”. < / P > < p > in addition to using the complete “fool mode” shooting, each shooting mode has the possibility and space to adjust the aperture, speed and sensitivity separately. A series of different adjustments can be made between the maximum and the minimum of aperture, speed and sensitivity, which is commonly referred to as increasing the aperture, reducing the aperture or increasing the speed, reducing the speed or reducing the sensitivity A series of instructions, such as sensitivity, sensitivity, etc. < / P > < p > we can adjust one, two or even three of the three indicators, or adjust only one of them. The purpose of adjustment is to achieve correct, appropriate and satisfactory exposure. < / P > < p > the early grading of aperture size is relatively simple and rough, which is generally arranged in the order of 2.8, 4, 5.6, 8, 11, 16 and 22. The range of different cameras is different, and the actual aperture size between adjacent from left to right is 2:1. For example, compared with 5.6, the aperture of 4 is twice that of 5.6, and the aperture of 5.6 is half of 4, and so on. < / P > < p > the hierarchical arrangement of sensitivity is 50, 100, 200, 400, 800, 1600, 3200 and so on. For the two kinds of sensitivity from left to right, the image quality of the left side is twice as high as that of the right side, but in terms of the “sensitivity”, it is twice as “strong” as that of the front. < / P > < p > however, the fineness and thinning ability of SLR cameras have been greatly improved and enhanced. Generally, two distinguishing points are inserted between the original two grades, so as to adapt to more refined adjustment requirements. < / P > < p > for example, in terms of aperture, two “nodes” 3.2 and 3.5 are inserted between the original 2.8 and 4. In fact, the “1” span between 2.8 and 4 is equally divided into three sections, and one adjustment to the right can increase 1 / 3 to achieve the effect of 1 / 3 + 1 / 3 + 1 / 3 = 1. There seems to be a conflict between such a classification statement and the original “increase one gear aperture” or “reduce one gear aperture”, and there is a dispute over whether it is “first class” or “first gear”. In order to solve this conflict, it is enough to say “increase 1 / 3 aperture” or “reduce 1 / 3 aperture”. In terms of exposure speed, 1 / 5 and 1 / 6 nodes are inserted between 1 / 4 and 1 / 8, and 1 / 80 and 1 / 100 nodes are inserted between 1 / 60 and 1 / 125. Although it is not necessarily a mark of “three equal parts”, the goal of realizing 1 / 3 + 1 / 3 + 1 / 3 = 1 is exactly the same. < / P > < p > it is better to run in small steps or flood water, which can leave more space for adjustment and comparison, and make the final exposure more accurate or in line with personality. < / P > < p > how to realize the setting of “flood irrigation” and “small step and fast run”? The method is to enter the main menu of the camera, find “exposure level increment” and “ISO sensitivity setting increment” two submenu, respectively give up “1” and select “1 / 3”. < / P > < p > is the level adjustment in the actual shooting process first small and then large or Although there is no specific dogma about “one-step approach”, it is better to follow the principle of gradual progress from small to large. As long as the conditions permit, you can choose different spans and levels, try to take a few photos, make full comparison and consideration before making choices. When the experience reaches a certain level, you can achieve “one-step arrival”. < / P > < p > in addition to the adjustment of aperture, speed and sensitivity mentioned above, as well as the exposure compensation of the camera and the exposure compensation of the flash lamp, it can also be implemented cautiously according to the principle of “running in small steps, comparison and selection”, and it is not allowed to “flood with water and reach the goal in one step”. This idea is also in line with people’s cognitive law. Huawei mate40 concept machine exposed, Kirin 1020 + curved surface full-scale screen, beauty hanging on iPhone 12

Author: zmhuaxia