[obican]

Ok,what do you mean exactly? 70mm at infinity to 100mm at MFD?

 

Do you realize that when one does not change focal length, FOV always will narrow towards MFD?

 

Actually, here you go

 



 

Screen capture I had made from LR some while ago. On the left is a Sigma 17-70 at 70mm. On the right is the Beercan at 70mm. Shot from the same spot, quite close to the minimum focus distance. Beercan image EXIF is being tagged at 75mm at the wide end btw, even though it's sold as a 70-210mm lens. 

 

Also, FOV will not always be narrower towards MFD. Nikon's old 70-200/2.8 that is being discussed here gets significantly wider at MFD. Even  you said so:

 

By the way, just to reiterate: All these lenses focus breathe (change FOV through the focus range).

It is just that some widen FOV towards MFD, and others narrow FOV towards MFD.

All a bother for video, but the narrowing is not a bother for photography.