Ask a few questions about photography.

Out-of-focus imaging is a new word, sometimes called defocus, blur, virtual image and so on. , which is commonly known as the background blur effect. Please refer to the ranking above for explanation. When shooting needs to create a shallow depth of field effect, generally speaking, the foreground and background of the picture are out of focus, showing a fuzzy effect, which is called "out-of-focus imaging quality". For SLR cameras, this quality is only related to the lens itself. Experience has proved that this kind of blur has a very important influence on the final expressive force of the image, so it becomes an important reference for evaluating the lens quality. Generally speaking, good blur should be continuous and uniform, and there is no obvious edge residue in defocus imaging. However, it is generally considered that the poor effect is called "out-of-focus bilinear". The fuzzy untitled contour is not uniformly defocused, but separated by several lines, forming something like a small bubble. This effect often interferes with the theme of the picture and affects the expressive force of the image (of course, there are exceptions in everything, and bilinear is used to do some special effects)

Pan-focus application plays an important role in photography. Pan-focus technology is often used in daily life. Fish-eye glasses and ultra-wide-angle lenses or wide-angle lenses are the best ways to use pan-focus. This technology can display images beyond the human eye. And most of them are small aperture applications. The correct use of pan-focus technique can make the work more interesting and create a sense of exaggeration.