When it comes to lens aperture, most people know that the larger the aperture, the smaller the depth of field; the smaller the aperture, the greater the depth of field. You also know that you want to shoot two stops smaller than the maximum aperture, but do you know the best aperture of each lens?

The best aperture of the lens refers to the best picture quality when the lens is in a certain aperture range. Note that it is not a specific aperture value, but a range. And it's not that bigger is better, and it's not that smaller is better.

Why does the best aperture exist? Many articles are ambiguous, leaving readers puzzled. The editor came to the conclusion through a lot of research: it must be related to the structure of the lens. We all know that a lens is composed of many lenses. For example, Canon EF 24-70mm f/2.8L II USM has a lens structure of 18 elements in 13 groups, that is to say, it has a total of 18 lenses. These 18 lenses can be divided into 13 lens groups, and some are 1 lens. In groups, some are two pieces in groups to achieve different functions.

We should know that, generally speaking, regardless of the quality and technology of the lens, the less the lens, the more realistic the image is restored, and the better the image will be. Therefore, the so-called optimal aperture is probably produced when the lens is switched to the lens group with the fewest lenses; if the quality and technology of the lens are considered, it can also be said that the lens is produced when the lens is switched to the lens group with the best lens quality. Or maybe they are both produced at the same time.

Of course, we should not rely too much on the best aperture, and we should not rely on the best aperture. Because the optical design of modern lenses has been done very well, compared with the best aperture, the performance in other aperture values ​​is sometimes indistinguishable by our naked eyes, unless you zoom in 400% to see. Therefore, use a large aperture when you need a small depth of field, and use a small aperture when you need a depth of field.