Hello there!
about Clive Milne post: I have seen the aberration magnitude of the book shown, it is for symmetric plossl not for asymmetric plossl (Clave') that was infact much more expensive to produce, it is a completly different thing!
about ausastronomer post: I am sure technology has improved light transmission, but can I ask you where have you found the graph attached to your post about Pentax, is it an official Pentax graph? Have you a link? Because if you take a look of the post of mplanet62 he has added this link:
http://www.canon.com/technology/s_la...ht/003/03.html
I don't know if the canon company is a lie, it could be, but they confirm what I say, I would like to understand more
CIAO
Fabrizio