Quote Originally Posted by Aristophanes View Post
It's also helpful to know that all optical design has tradeoffs. Sure, you can get a sharp 1.4, but to get that usually there is corner falloff. They have to make choices. It's just the way optical physics works. There is no optimum design. price and size also impact.

Also, as the colour film (and TV) era dawned, many fast lenses of the 1970's to 1980's were actually designed to be less than sharp, and one way to do so was shallow DOF. Colour film was often too revealing of blemishes etc., so "soft" became an aesthetic.
While in principle I agree that that all optical design is a tradeoff, I disagree with your implication that that means that there are no fast lenses out there with great all-round performance.

Using the same Nikkor 35mm f/2.0 AIS as an example, while a fine lens in its own right, I have 35mm lenses which:
1) are sharper wide open
2) vignette less
3) distort less
4) flare less
5) have more or less the same size & weight
Admittedly those "better" lenses were once much more expensive when new. But the tradeoffs can be much less than you seem to imply.

That said, I'm a fan of very compact and corrected slow lenses as well...

I've never ever heard of lenses expressly being designed to be less sharp, unless you're talking about portrait and/or "soft" lenses