[Leica] Bokeh and quantification

[walt at waltjohnson.com (Walt Johnson)]

It would seem the search for good bokeh should be confined to earlier 
lenses designed before computers took over?Another element of this bokeh 
discussion seems to be lost on many of us. I've never seen a strong 
image weakened by bad bokeh. I've never looked at an image which made an 
effective statement in the manner only photography can and said what 
great bokeh. This term, seemingly given more appeal to some by its Asian 
flavor, misses the point. Pick up a copy of /Black Sun /which includes 
work by several well-known Japanese photographers. Eikoh Hosoe, Daido 
Moriyama, and Shomei Tomatsu may have a lot of bokeh but no one mentions 
it. The bottom line seems to be

we can talk about images or we can shoot them..............both pursuits 
are interesting but only one proves its point.

Happy Bokehing

Walt

Marty Deveney wrote:

>My interest has been, not that boke, or the character of the OOF areas
>can be measured, but that the characteristic of the lens design which has
>the effect could be measured. Many just mention a circular aperture but
>since it is the character wide open which is of most interest to me
>clearly the shape of the aperture has no
>influence. Canon state in their Lens Work publication, without
>explanation or discussion, that if the saggital and radial MTF curves run
>together the boke will be pleasing. This completely agrees with my
>experience in the case of the lenses I have been able to find MTF curves
>for so I am prepared to believe it, but I'd like to know why. I was BTW
>one of those who sold my CV 50mm f1.5 Nokton because of the boke being
>awful. My favourite 50 is my pre asph Summilux, though I have never seen
>never mind used the new one.....
>
>This is relatively simple.  The differences between tangential and
>saggital MTF curves indicate how well off-axis aberrations are corrected,
>including astigmatism and field curvature; properties that affect bokeh. 
>Bad bokeh is typically associated with these off-axis aberrations, which
>is why a significant difference in tangential and saggital MTF
>is indicative of the quality of bokeh.
>
>Marty
>
>  
>