From: Carl Weese (cweese@earthlink.net)
Date: 03/28/01-07:49:10 AM Z
--
Web site with workshop information and
**NEW PICTURE GALLERIES**
http://home.earthlink.net/~cweese/
----------
>From: Sandy King <sanking@hubcap.clemson.edu>
>To: alt-photo-process-l@sask.usask.ca
>Subject: Bokeh, was Re: Direct negatives from slides
>Date: Wed, Mar 28, 2001, 12:31 PM
>
> Carl,
>
> Yes, I remember making that comment about the print from the 16 1/2" Dagor,
> though I don't recall that you explained the effect as the result of bokeh.
> So what is bokeh caused by, some kind of combination of lens aberrations
> that makes the transition from in-to-out of focus smoother.
>
> Sandy King
>
>
>
>>
>>Actually, you spontaneously commented on the excellent bokeh displayed by my
>>16.5 inch A.O. dagor when looking at the picture of the overpass with sumac
>>in the shadowed foreground. You noticed that the f/g looked wonderful even
>>though it couldn't possibly be in focus: that's a perfect example of a lens
>>with favorable bokeh characteristics. The smoothness of transition from
>>in-focus to out effectively extends the depth of field.
>
>
>
>
> Lenses with really
>>awful out of focus character show a sudden, harsh transition. With strong
>>selective focus, the blurred areas can look almost as weird as the
>>donut-shapes you get with a mirror lens. In one example I saw, there was a
>>liquor bottle in the background. In the lens with unfortunate bokeh, you
>>could more or less tell it was a bottle. In the lens with beautiful bokeh,
>>you could tell what brand it was because the logo, though blurred, was
>>recognisable even though technical depth field was of course the same. Wish
>>I remember where I saw that pairing.
>>
>>The first time I encountered the concept stated as such had nothing to do
>>with Japan: Bill Pierce about ten years ago told me about a conversation
>>he'd had, ten years earlier still, with the Leitz designer responsible for
>>the Noctilux. What he said was simply that at f/1, invariably most of the
>>picture will not be in the plane of good focus. So it makes sense to pay
>>attention to the look of the out-of-focus image when designing the lens. In
>>fact, I'd been aware of the difference on a gut level since the 1970's when
>>I began using Leitz lenses for all my personal work even though I had a
>>complete set of Nikons for commercial assignments. Art directors were happy
>>with chromes from the Nikkor glass, but my b&w prints from Letiz lenses were
>>invariably more pleasing, and this smoothness of focus transition is a vital
>>element of the difference. But most of this work was in low light with
>>lenses near wide-open. Most commercial work had artificial lighting and deep
>>focus.
>>
>>With a 6x9cm stopped down to f/32, there won't really be any out of focus
>>stuff unless your subject is quite close, within 4 or 5 feet I'd guess.
>>
>>---Carl
>
>
>
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