I was confused with teleconverters.
Let's say with a 1.4X TC attached to my lens, the same subject will be magnified by
1.4 times(?). The loss of light will be reduced by 1.4 stops, for example from F/2.8 to
somewhere arround F/5 (between F/4 & F/5.6). If it is a fictitious 1X TC, it will not
magnify my subject, but it will change the light admission of the aperture from F/2.8
to F/4.0, while DOF remain unchanged?
Is my understanding correct?