The Avenon at f/2.8 is better than the CV at f/4 actually. I'm not sure about, what Y.K. Optical had claimed, that it is an alternative to the ASPH Leica 21/2.8. But it's definitely cheaper, smaller and a better traveller lens. It is, IMHO, not as tack sharp as the CV 15/4.5 though, but still very strong. It's yet underrated.