Optical photographic background

ISO is the sensitivity (about 200 OK in daytime), and it is not blurred. In general, we don't want to use high ISO. First, it is unnecessary. Second, because the ISO is too high, the noise will increase.

When it comes to ISO (sensitivity), everyone will definitely think of a sentence "Use the lowest possible ISO". Why is this? We will know the reason by the following typical high ISO photo!

In the picture, those unnatural white dots that fill the whole picture are called noise, which is a "specialty" of high ISO photos. The higher the ISO, the more obvious the noise is. Noise will lead to the lack of detailed information of the picture, which will seriously affect the picture quality. Therefore, in most cases, we should use the lowest possible ISO. But things are not absolute, and high ISO is not a scourge. Sometimes, we can use high ISO safely, or we must use high ISO.

And blur is: AV mode: aperture, which is generally 1- 16 level (8 in the middle).

Equivalent to queuing, from 1- 16. If you want a portrait, 2-4, preferably, is equivalent to, you lock the face, take it as the center, and the back will be blurred.

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