What is the focal length that a novice photographer must learn?

Lead: Focus is an important element in our photos. Using lenses with different focal lengths will greatly enhance the composition of our photos.

What is the focal length that a novice photographer must learn? How to find the focal length of a lens?

The focal length is usually clearly displayed on the lens, usually expressed in millimeters (mm). The fixed-focus lens will only have one set of numbers (for example, 50mm), while the zoom lens will have two sets (for example, 18-55mm), indicating the zoom range of the lens.

In actual shooting, different focal lengths will affect the size of the object in your photo. The longer the focal length, the larger the object, the narrower the viewing angle, the stronger the oppressive feeling and the shallower the depth of field.

Take this lens as an example. The focal length written on it is exactly 35mm-70mm.

Focal length and viewing angle

When you shoot an object, the focal length of the lens determines its size in the photo. The longer the focal length of the lens is, the narrower the viewing angle will be, so the subject will be enlarged correspondingly, and the viewing angle will be narrowed, which is closer to the subject in our view, that is, enlargement. The picture on the left simply shows the actual difference between the long focal length and the short focal length.

Focal length and viewing angle

The world we see with our eyes includes concepts such as distance, size, relative distance between objects, and the most important concept is that the same object is large from a distance, but it becomes smaller from a distance. This is called perspective. When you take a close/far photo of the target, the object becomes bigger and smaller in the picture, which is called perspective change.

Perspective is a powerful composition tool in photography. Photographers create different photographic effects by choosing lenses with different focal lengths. Please note the lamp distance between the first two branches in the picture on the right:

(Above) When shooting with a wide-angle lens, the light that appears visually at close range is very large, while the distant view is much smaller.

(Below) When using a telephoto lens, the size ratio of the subject and the background will not be too different.

Focal length and composition

Many people think that zooming in is just to save your feet, so that you don't have to go near objects to shoot, or just shoot distant things, such as birds. In fact, the perspective and compression caused by different focal lengths will bring great differences in composition.

For example, on the left, the two sculptures in the photo are about the same size, but the backgrounds are quite different. Shoot with the focal length of 18mm above, and shoot with the distance of 55 mm below. As a result, with the wide-angle shot above, the background is far and wide from the subject, and there are many things to see. In the lower photos taken from a distance, the background is closer, but the viewing angle is narrower.

Compare the following two pictures. The left side is shot at close range with a 18mm wide-angle lens, and the right side is shot at a long distance with a 55mm telephoto lens. The baby's size is similar, but the head-to-body ratio is obviously different. The head on the left is relatively large, and the proportion on the right is reasonable and normal. The arrangement of crib brackets is also different. The picture on the right is obviously neat, but the shooting range is narrow and the left side is diffuse. It can be seen that the visual effects obtained by using different focal lengths are also very different.

18mm

70 mm

24 mm

105mm

50 mm

250 mm

What lens focal length should I use?

Generally speaking, people will use the following categories:

Lens focal length: the general shooting purpose is less than 2 1mm super wide-angle lens, which is used to shoot vast scenery. 2 1-35mm wide-angle lens is used to shoot general scenery, 35-70mm is used to shoot realistic photography, and 70- 135mm is used to shoot distant sports, birds and wild animals. People usually call 50mm as the standard focal length, because its visual angle is closest to people's eyes. As for how to use each focal length, the above is for reference only. Photography can have many changes, so don't be limited by data.