A little question about photography ~

Aperture is a measure to control the size of external light source entering photosensitive element. The smaller the aperture value, the more light the photosensitive element receives, and the larger the aperture value, the less light the photosensitive element receives.

Aperture directly affects the saturation, brightness and background clarity of the picture color. At the same focal length, the smaller the aperture value, the less background you can see (the term is depth of field, which means that the background is very shallow and close from a vertical angle), and the more blurred the background is. The larger the aperture value, the more background you can see (this term is called scene depth, which means the background is very deep and far from the vertical angle), and the clearer the background is. At the same time, the color will get darker and darker.

85mm refers to the focal length when shooting. The focal length directly affects your viewing angle. From the viewfinder, the greater the focal length, the less the fixed fuselage can see, and the details will be enlarged; The smaller the focal length value, the more fixed main parts you can see and the less details you can see. For example, when the focal length is 85mm, you see a still figure in the camera as a bust, then the figure you see in the 50mm camera may be the whole body or even more; The person you see from the focal length 150mm may be a bust or even a headshot.