How to understand the speed and sensitivity of aperture and shutter, and how to apply it?

The decisive factors of exposure are aperture, shutter and iso sensitivity, and the combination of these three parameters determines a correct exposure.

Generally speaking, unless the light is very dark and manual shooting is needed, there is no need to set the iso too high. If the iso is too high, it will increase the noise, resulting in a decline in image quality. Usually iso can be fixed at 100 or 200.

When iso is fixed, the only factors that determine exposure are aperture and shutter speed. Therefore, under the same exposure, the larger the aperture, the faster the shutter speed.

For example, iso 100, when the aperture f4 and shutter 1/500 seconds, the exposure is correct;

Iso is still 100. When the aperture is changed to f8 and the shutter speed is1125 seconds, the exposure results at this time are exactly the same as those taken with the above parameters.

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Aperture not only determines exposure, but also determines depth of field. The larger the aperture, the shallower the depth of field, and the better the background blur effect, which is conducive to highlighting the subject and streamlining the picture. This setting is often used when shooting subjects such as portraits.

The smaller the aperture, the greater the depth of field, which can make the picture clear far and near. This setting is often used when shooting landscapes.

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Shutter speed not only determines exposure, but also satisfies different shooting intentions.

Using high-speed shutter can solidify the moment of motion; Using slow shutter to pan can make the moving object clear and the background blurred, resulting in motion blur effect, thus reflecting the sense of motion.

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If you just play, look up information on the internet and look at other people's photos on the forum, it will be greatly improved.

The book recommended the Photography Textbook of New York Institute of Photography, which explained in detail the exposure, composition, lighting and many other aspects.