18-200 why is the lens called the dog head?

According to the query industry encyclopedia, 18-200 lens is called the dog head for the following reasons:

Because 18-200 lens is relatively cheap, and the sharpness of this lens is not high, and the distortion and dispersion are not handled very well. In the primary stage of optical products, some popular lenses are seriously distorted, and some exaggerated claims are that people can shoot their heads into dog heads. That's why it's called dog head.

In film and television, the lens has two fingers, one refers to the optical components used by film cameras and projectors to produce images, the other refers to the continuous picture taken from power on to power off, or the fragment between two editing points, also known as the lens.