Something I've been asking myself for quite some time is the following:
Why is it that changing the focal length changes the angle of view and changing the aperture changes the angle of the incoming light rays that hit the sensor, but these two principles don't interact with each other?
From the CiC tutorials I can't figure it out:
vs
The thing I thought of is that the above question explains why you have a much shallower DoF when shooting rather close to the lens, but it doesn't answer to why it doesn't work vice versa: Why changing aperture doesn't change the angle of view?