Re: [Leica] spherical aberrations was more d.o.f. with asph?

["Bud Cook" <budcook@attglobal.net>]

Here are some possible explanations for good bokeh that I found elsewhere:

- - Radial and tangential aberrations to be about the same.
- - Round diaphragm.
- - No central obstruction (mirror lenses have very unnatural bokeh).
- - Spherical aberration is tolerable and even beneficial.

Spherical aberration seem to be like even harmonic distortion in amplifiers.
It's not irritating and in fact, it can be pleasing.

Bud

> "Henning J. Wulff" wrote:>
>
>             There is a certain truth to this,
>             as the additional spherical aberration
>             that the pre-ASPH Summicron has makes
>             particularly the out-of-focus areas
>             appear softer, broader (and smoother)
>             than the ASPH will render them.
>
>             [snip]