> Now, here's the kicker: the bigger the focusing lens is, the larger the cone of light rays is, meaning the the out of focus parts of the image will be more out of focus
From the page [0] it takes the depth of focus image from:
> [Depth of focus] differs from depth of field because it describes the distance over which light is focused at the camera's sensor, as opposed to the subject
The first quote is clearly talking about depth of field, not depth of focus. See also what I quoted in my original comment.
Depth of focus isn’t really relevant to the rendering of an image (except insofar as you want your camera to be built to sufficient tolerances that a sharp image can be obtained when desired).
I assumed you were using “depth of focus” to mean “depth of field”. If you really meant “depth of focus”, then I would say you are mistaken in thinking that the author’s goal is to obtain a narrow depth of focus.
The first quote is definitely talking about depth of focus; the linked image talks about depth of focus and how it compares to depth of field. As I understand it, depth of focus has a similar effect to depth of field. If your rays diverge more quickly on the side of your sensor, you will have a blurrier image for the same distance from the focal plane. Otherwise, how do you think depth of focus presents itself in the final image?
> Now, here's the kicker: the bigger the focusing lens is, the larger the cone of light rays is, meaning the the out of focus parts of the image will be more out of focus
From the page [0] it takes the depth of focus image from:
> [Depth of focus] differs from depth of field because it describes the distance over which light is focused at the camera's sensor, as opposed to the subject
[0] https://www.cambridgeincolour.com/tutorials/depth-of-field.h...