"Round" Lens Diaphragm? See This! :-o

When some Pentaxians rave about the "round" diaphragm of the "new" DFA 100 Macro lens of Pentax, which has only 8 aperture blades actually, I think we need to look at something that is really great in this regard, which came from the old days:-




Could you count how many aperture blades this lens has? It has 16! And, most importantly, the opening is really perfectly round, no matter at *any* f-stop that it is set!

Well, a circle is essentially a multi-polygon with numerous number of sides. So, how a lens with 8 blades could be "perfectly round" when it is only 8, just? :-)


Related:-

DFA 100 Macro WR - Brief Hands-on Impressions