Yes, the f number is the ratio of the lens aperture diameter to the focal plane distance. As a consequence, the effective f number varies as the on-film magnification varies. The f numbers engraved on a lens are typically the f number for the lens when it is focused at infinity.

The Zeiss Biogons and Hologons are not retrofocus designs.

The 16mm Hologon is a fixed aperture (f8 at infinity) WA lens that provides nearly rectilinear coverage of the 35mm format.