Freddy, you should add these excellent shots to the Sample Archive.
I'm so excited for you Nick.
Most older lenses only stop down to f16. Most modern lens designs can go one stop smaller to f22. I'm guessing your edition is a later model of the same lens.
F22 would not be of much use anyway though due to diffraction: Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks