Consider the angle formed by the left side of the picture, the camera/viewer, and the right side of the picture. The higher the zoom (or the crop), the smaller

Consider the angle formed by the left side of the picture, the camera/viewer, and the right side of the picture. The higher the zoom (or the crop), the smaller this angle is. It's called field of view (FOV). You've seen this in horror movies when they pull the camera back while zooming in (or out). The protagonist fills the same amount of the screen while their face distorts and the angle spanned by the background narrows (or expands). The fireplace in the background that originally was a small part of the background now spans the whole background. Or the crowd. https://filmschoolrejects.com/wp-content/uploads/2021/01/Jaws-dolly-zoom.gif https://filmschoolrejects.com/wp-content/uploads/2021/01/Jaw... That's the kind of distortion under discussion. You're right that zooming and cropping are the same, but that doesn't actually refute the point, because both affect FOV the same way, and FOV differences are the topic under discussion.