The lens characteristics of food documentaries are standard fixed-focus lenses. Primelens refer to lenses with only one fixed focal length. There is no focal length, or there is only one field of view. Primelens do not have a zoom function. .

The design of a fixed-focus lens is much simpler than that of a zoom lens, but generally a zoom lens will have an impact on the image during the zooming process, and the biggest advantage of a fixed-focus lens over a zoom machine is focusing. Fast speed and stable imaging quality. The images of moving objects captured by many digital cameras with fixed-focus lenses are clear and stable, the focus is very accurate, the picture is delicate, the graininess is very slight, and the metering is also relatively accurate.