Xiao Bai just plays photography. If I shoot a landscape and focus on one mountain, is only one mountain clear and the others are a little blurred?

Hello, focal plane. Terminology for photography. When infinitely parallel light enters the lens of a camera, it will refract to the main axis of the lens and converge to one point, which is the focus of the lens, that is, the clearest point of the scene image taken by the lens. The plane perpendicular to the main axis formed by the main focus and many secondary focuses of the lens is called the focal plane. The place where the photosensitive plate is installed in the camera is the focal plane position.