On Sat, 22 Jun 2002 06:39:28 GMT, handerle@klosterneuburg.net (Dr. Heinz Anderle) wrote:

>This question is not intended to burst into a flame-war.
>
>Although it is recommended not to use the b-word in this group, I
>would be interested how a smooth rendition of out-of-focus objects
>especially from normal and portrait lenses can be achieved.
>
>I have read that Leica and Minolta lenses are the best in this
>category, and that especially some Nikkors aren't anything but sharp
>with a strange double-contoured blur. Sometimes this really distracts
>from the main object (even when used at large apertures like f/2,8).
>
>From the lens drawings I have seen I can only tell that the lens
>designs for each focal length look quite similar (but I am not an
>expert). I have also read that optimizing a lens design for a high and
>contrasty resolution may deteriorate the b-word.
>
>Are there any trade-offs when a lens is de-optimized for a good
>unsharpness (e. g. more coma, more distortion, shallower depth of
>field?)
>
>How would other lens brands be rated (Zeiss, Pentax, Olympus, Canon) -
>and what about the independent lens makers?
>
>Thank you -
>
>Dr. Heinz Anderle
>living with Nikon non-b-word...

The poster above appears to have been unnecessarily rude...
Bokeh is quite real, but some of us prefer the "hard"
"bad" bokeh to the supposedly "good" bokeh. In the 500mm
f8 early Nikkor mirror, the high-contrast "edgy" out of
focus characteristic appears to usefully extend the
otherwise very shallow DOF one would expect from a lens
of this type. Same for "universal DOF" landscapes with
shorter lenses, where "good" bokeh lenses have more
trouble covering crisply the infinity-side of focus
compromised for maximum DOF. Also, it is possible to
take photos with "bad" bokeh lenses that would not be
as successful with "good" bokeh lenses (for examples
of these, see www.David-Ruether-Photography.com/sunplant1.html).
Other comments: some of us consider everything within
the frame to be "subject", as opposed to "subject and
background"; "good" bokeh is the result of undercorrected
spherical aberration, which does have some negative
consequences (some newer Nikkors are designed for this,
and a couple allow user-adjustment!); looking at lens
diagrams will give you no idea of how the lens will
perform; softer lenses often have a bit greater DOF,
in that it is harder to see the exact plane of focus;
if you are interested in Nikkors with "good" bokeh,
look for those designed for this, or get the AF
105 or 135mm FLs, which are also appropriate FLs
for much of portrait work...
(Ah, I managed to use the "b-word" about 8 times above,
so......;-)