What is the maximum magnification of the lens?

The magnification of the lens refers to the maximum magnification of the lens. Generally speaking, it is the magnification at the maximum focal length and the nearest focal length of the lens. The magnification of the lens refers to the comparison data between the ratio (width or height) of the captured image and the ratio of the camera sensor.

For example, the sensor width of 135 camera is 3.6 cm. If the largest image taken is 3.6 cm (the scale in the image spans 3.6 cm from left to right), then we can say that the magnification of this lens is 1. If the largest image taken is 7.2 cm (the left-right span is 7.2 cm), then we say that the magnification of this lens is 0.5.

There are two ways to express the magnification of a lens, one is the magnification, such as1:3; The other is decimal, such as 0.33.

The relationship between the two is:

The larger the number to the right of the contrast number, the smaller the magnification; The larger the decimal, the greater the magnification. For example: 1: 8 is 0.125; 1: 5 is 0.2; 1: 3 is 0.33; 1: 2 is 0.5, 1: 1 Yes 1.

Therefore, when the viewing ratio is large, the maximum magnification of this lens is poor; When there are many decimals, the maximum magnification of this lens is strong.

The magnification of the lens means that the original imaging area of the subject can be changed by adjusting the lens. Although it is called magnification, some shots may play a role in reducing it. If the product logo is 1:4, the lens can be enlarged by up to 4 times.

The magnification of the macro lens is the macro effect of 1: 1 and 1:2, and these ratios refer to the maximum magnification of the lens. The magnification is represented by 1: x, and the magnification = image size (actual size of the subject). Generally, any number on the left or right is classified as 1, which is generally expressed as1:x or ×: 1.

The former means that the actual size of the subject is x times that of the image, and the latter means that the size of the image is x times that of the subject. The "image size" mentioned here refers to the size projected on the film or photoreceptor, not the size on the photo. 1:2 means that the actual size of the subject is twice the size of the image, or the size of the image is 1/2 of the actual size of the subject. Many lenses have macro function, but they are not macro lenses. Macro function is an additional function. Strictly speaking, only a lens with a magnification of 1: 1 is a real macro lens.

Macro lens and 1: 1 magnification shooting:

For example:

If the length of the object is 10 mm and the image on the negative is 10 mm, the lens magnification is1:1;

If the length of the object is 10 mm and the imaging on the negative is 5 mm, the lens magnification is1:2;

If the length of the object is 10 mm and the image is 2 mm on the negative, the lens magnification is 1:5.

According to the magnification, macro photography can be subdivided into close-range photography and ultra-close-range photography. There is no strict definition, but the general definition is:

Close-range photography: the magnification is1:10 ~1:1;

Ultra-close photography:1:1~ 6:1; (More than this magnification, it begins to enter the scope of photomicrography. )

Scale display of magnification on lens

The maximum magnification of the lens is achieved at the maximum focal length (there is no fixed focus) and the nearest shooting distance. We usually call a photographic lens with the maximum magnification of 1: 4 ~ 1: 1 which can focus at infinity a macro lens.

If you use the same magnification, the longer the focal length, the farther away from the subject, which is suitable for shooting fine subjects such as insects.

Finally, the maximum magnification refers to the maximum image formed by the image plane when shooting at the nearest focal length. At this time, the ratio of the height of the image to the height of the object is the maximum magnification, which is closely related to the nearest focal length, and the maximum magnification can be obtained when shooting at the nearest focal length.

But the focal length of some lenses is not fixed, but zoom. If it is zoom, the maximum magnification is also related to the focal length of the lens. When shooting with a zoom lens, the maximum magnification can only be achieved by using the telephoto end (that is, the maximum focal length) of the lens.

For example, the focal length of Canon lens ef-s 18- 135mm f/3.5-5.6 is18-135mm. When shooting with its 18mm short focal length, its nearest focal length is 0.49m and its magnification is 0.04 times. We can further understand what the nearest focal length and maximum magnification are through the imaging schematic diagram of a single lenticular lens with the following themes: