It is equivalent to 38- 1 14 mm of a 35mm camera.

For photographers, it is necessary to master basic concepts such as focal length, zoom and digital zoom. If you are still confused about these, I believe this short article will help you.

First, explain "what is focal length" with a 35mm interchangeable lens SLR camera. "Focal length" refers to the distance from the focal plane of the lens to the imaging plane (i.e. film). The plane where the focus is located is the "focal plane", and "focal point" means that "the light of the photographed object will converge to one point when passing through the lens, which is to take the focus".

The focal length of a lens is in millimeters. For example, the focal length of the ordinary lens of 135 camera is generally about 52mm and so on. The focal length of the lens determines the shooting field of view of the camera, and the focal length is small and the field of view is large, and vice versa. The so-called "general shot" refers to "a shot in which the proportion of the display object is not much different from the actual proportion of the scene".

No matter what brand of the same type of camera, as long as the focal length is the same, the shooting angle of the camera is the same. For example, in the 120 camera, the field of view of Hasselblad and Mamiya's 85mm lens is the same. For different types of cameras, even if the focal length is the same, the field of view angle is different. For example, the 50mm of 120 camera has a small wide angle, and the field of view is larger than that of 135 camera.

Of course, when you use a long focal length lens, the field of vision will be reduced and the subject will be enlarged in the framing composition, so you can see more and more detailed details of the subject. Therefore, when a subject needs to be emphasized, a long focal length lens is often used.

optical zoom

"Zoom lens" refers to a lens whose focal length can be changed. According to the preset focal length, the picture can be optically enlarged or reduced while shooting to present a larger or smaller field of view. Before the appearance of digital cameras, there was no so-called "optical zoom", only "zoom". However, after digital camera brought the concept of "digital zoom", in order to distinguish two different zoom modes, the original meaning of "zoom" was defined as "zoom in the optical range". However, traditional cameras still only have optical zoom, and there is no problem of digital zoom. Therefore, when limited to the discussion between traditional cameras, photographers are still used to using the word "zoom".

For digital cameras, "optical zoom" does not change the size or resolution of the picture, and the number of images used to describe the picture remains unchanged. This is the fundamental difference between "optical zoom" and "digital zoom", which is reflected in the image, that is, the image quality will be different.

digital zoom

A digital camera equipped with a fixed focal length lens can often simulate optical zoom to form a zoom picture, which is called "digital zoom". It works in a way similar to enlarging a part of an image in a computer, but the difference is that "digital zoom" is done directly on the CCD during shooting. To be exact, "digital zoom" is just a cropping tool, because it can cut off a part of the image-this part is invisible when using a telephoto lens, and only the selected local area is stored.

But the pixels of the original frame used to take pictures are the same, which may mean that no matter how you zoom digitally, the pixels contained in the fixed frame are fixed, representing the original unfocused picture. Therefore, the digital zoom image is smaller than the original image, but the definition is the same ―― however, if the interpolated image is the same size as the unfocused image, its definition is much worse, because interpolation will affect the definition.

Remember, any photo editing program can achieve the same effect as digital zoom. You can use software to cut out any image size you need, which is more flexible than digital zoom, because you can select any area, and digital zoom can only use the central part of the whole photo.

If there is any advantage of "digital zoom", it is that the camera can measure the light in the "zoom" part, thus avoiding the interference of other scenes on the light measurement and allowing you to make more accurate exposure.