70-200 F4 Heavy Breather?

Yes, I have noticed too that people seem to think calculated focal length changes mean focus breathing, but it does not... Cine lenses deliberately change focal length to prevent breathing during focussing.

With my Canon 70-200mm f4 L USM, the calculated focal length at MFD is similar to the f2.8 VR II or the f4 VR. But the FOV/AOV narrows. So, while the focal length shrinks, the accompanying FOV/AOV is getting more narrow.

The problem with the AF-S 70-200mm f2.8 VR II is that the FOV/AOV gets quite a bit wider instead.

There is a silly trick I maybe found to determine if/how a lens focus breaths. Calculate the focal length the WRONG way, by not taking the front nodal point into account with the subject distance, but by ignoring the lens totally and taking the film/sensor plane instead.

Lenses which will get a more narrow FOV "increase" in (wrongly) calculated focal length, lenses which widen the FOV (like the f2.8 VR II) do show a shortening of the (wrongly calculated) focal length. I have no lens which does not breath one way or another to some extent, as far as I know, so I can not "test" if this trick will show the (wrongly calculated) focal length to stay the same when there is no breathing.