Archived posting to the Leica Users Group, 2000/08/27

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Subject: Re: [Leica] Bokeh vs. Nukeh
From: John Brownlow <john@pinkheadedbug.com>
Date: Mon, 28 Aug 2000 02:11:24 -0400

on 27/8/00 11:07 pm, Mark Rutledge at markrut@ticnet.com wrote:

> Maybe bokeh has more to do with the "art" aspect of photography rather than
> the technical side. Emotion vs quantifiability. Images (painting, photos..)
> can move us in a way we cannot describe...beauty isn't measurable. Just a
> guess!

I think bokeh is pretty measurable. Just no-one measures it yet. It's pretty
simple. You just look at the way the lens renders out of focus point sources
at various distances. You  measure the light intensity from the centre of
the point outwwards along a radius. This spread function defines the bokeh
of the lens, to a VERY good first approximation, since any image cam ne
considered as a collection of point sources.

That's it. Period. It's not difficult, complicated or airy fairy.

The corollary of this is that a simple test for a lens' bokeh, as anyone who
cares about it knows, is to look at out of focus specular highlights.
Diffuse circles = creamy bokeh. Hard edged circles = sharp transitions in
the out of focus areas (is there a word for this?). Donut shapes (bright
rings) = pronounced Ni-Sen bokeh, very painterly and textural, like the lux
50.

You don't care about bokeh? Fine. But my point of view is that a
photographer should be in charge of every element of his/her craft. Grain,
tonality, sharpness, bokeh and so on. Of course everyone knows the picture
comes first. But photography is a craft as well as an art.

Why do I care? I just developed twenty five rolls. Pretty much all of it was
shot wide open on either the 35/1.4 or the TE 90/2.8. I have way more stuff
out of focus than in focus. Thank God for nice bokeh!


- -- 
Johnny Deadman

http://www.pinkheadedbug.com

Replies: Reply from "Mark Rutledge" <markrut@ticnet.com> (Re: [Leica] Bokeh vs. Nukeh)
Reply from Shel Belinkoff <belinkoff@earthlink.net> (Re: [Leica] Bokeh vs. Nukeh)