How far is hyperfocal distance?

Hello ~ Most of the applications in hyperfocal distance were before the popularity of autofocus. Journalists often use hyperfocal distance to capture people. Now, however, autofocus almost makes up for this. Generally, a small aperture is used to shoot scenery, even a tripod above F 16, regardless of the problem of hyperfocal distance. In order to popularize photography knowledge together, I still send out the calculation formula table. As can be seen from the formula, the back depth of field >: the foreground is deep. It can be seen from the formula of depth of field that the depth of field is related to the aperture used by the lens, the focal length of the lens, the shooting distance and the requirements for image quality (expressed by the size of the allowable dispersion circle). These factors affect the depth of field as follows: (1), lens aperture: the larger the aperture, the smaller the depth of field; The smaller the aperture, the greater the depth of field; (2) Lens focal length: The longer the lens focal length, the smaller the depth of field; The shorter the focal length, the greater the depth of field; (3) Shooting distance: The farther the distance, the greater the depth of field; The closer the distance, the smaller the depth of field. Using the formula of depth of field calculation, we can calculate a Jing Shenbiao for our daily photography (because the calculation is complicated, you can't calculate it on the spot for the time being), but some books also provide ready-made Jing Shenbiao. The following is the Jing Shenbiao provided in the book (this is provided by Nikon for Nico lens) for your reference. Hyperfocal distance's definition: Under the premise that the focal length and aperture of the photographic lens are determined, the photographic object distance at the maximum depth of field can be obtained, which is called the hyperfocal distance at this focal length and aperture. The above is hyperfocal distance's definition, which seems a bit confusing. Besides, what's the use of hyperfocal distance? To be clear, we use the depth of field scale above to tell it: I believe this depth of field scale can be understood at a glance: at present, the focus is 2M, and you can see that there are two indicator lines on both sides of different aperture values. These two lines represent the clear range of foreground and background when the aperture is at a distance of 2M. For example, if you use an aperture of F= 1 1, then the clear distance is about 1.5-3M. This is the case when the lens is focused at infinity. If you shoot the scenery, you can see it clearly with the aperture F= 16, about 4.5M. This kind of focusing is not the best, because the back depth of field is not used at this time.

If the focus is 4.5M, it can be found that when the aperture is still F= 16, we use the back depth of field of F= 16: the back depth of field indicates that the line pair is at infinity, so that the focus not only ensures the definition at infinity, but also refers to the foreground depth of field of 2.2M, and the clear range is more than 2M in front of Figure 2, and the maximum depth of field is obtained. This is the "hyperfocal distance" focusing method, and the focusing position of 4.5M is called hyperfocal distance. Hyperfocal distance's method is often used in snapshots, because it is within my known range (for example, beyond 2.2M mentioned above), so there is no need to focus. You can grab time, capture shots, and ensure clarity at the same time. So reporters and the like are more popular.

The calculation of hyperfocal distance distance is complicated, so if your lens is attached with a depth scale, you can aim the back depth line of the selected aperture value at infinity when focusing, without calculation, which is very convenient to use. This is also a great application of the depth of field ratio in the lens. Of course, when we don't have this ruler, we'd better use the Jing Shenbiao tool or rotate the depth ruler.