— in lenses with a fixed focal length, the angle of view also remains constant; in other words, in such models it is impossible to zoom in and out of the image due to the lens settings. On the one hand, this makes "fixes" less versatile compared to models with a variable focal length. On the other hand, the optics are simpler, lighter and more compact, it is easier to provide high aperture in it, plus a smaller number of moving elements has a positive effect on reliability. And the mentioned impossibility to change the viewing angle in some genres of shooting (for example, portraiture) is simply not required.
