[Brightcolours]

FoV is usually expressed on degrees, and then angle of view and field of view are the same thing.



"In photography, the field of view is that part of the world that is visible through the camera at a particular position and orientation in space; objects outside the FOV when the picture is taken are not recorded in the photograph. It is most often expressed as the angular size of the view cone, as an angle of view."

http://en.wikipedia.org/wiki/Field_of_view



Even if one does not want to express FoV in degrees, but in area of subject matter, they still are totally linked (it is impossible for one to change and the other not to change accordingly:

http://martybugs.net/blog/blog.cgi/learning/Field-Of-View-And-More.html

http://www.acapixus.dk/photography/angle_of_view.htm

So, whether one wants to express field of view in degrees or in a percentage of the distance, or in some other way, still FoV and AoV are totally linked. If you see a more narrow FoV the AoV is smaller. If you have a bigger AoV the FoV will be wider.

For the FoV to change, the AoV has to change.





Anyway.... the fact remains that the Nikon 70-200mm f4 VR does not show focus breathing like the f2.8 VR does. You will not see the FoV (AoV) "breath" as you go through the focus range, or at least not get so much wider as with the f2.8, probably a little bit more narrow like with the Canons.