TAKO. INTERNET SEIT 1996.
Olympus-OM

Re: [OM] Lens design, bokeh, etc.

Subject: Re: [OM] Lens design, bokeh, etc.
From: Chris Crawford <chris@xxxxxxxxxxxxxxxxxxxxxx>
Date: Fri, 04 Nov 2011 19:16:36 -0400
I think that is a quality of large format itself, not the lens designs.
Large format lenses are actually not very sharp, because they're typically
stopped down quite a bit. That portrait of Churchill may well have been
shot with the lens at f22 or 32, maybe even 45. It was done on 8x10 film,
if I remember right, which would have meant a 300mm lens (if he used a
'standard' lens). A 300mm lens or anything around that focal length, has
very little depth of field, even at f32, when close enough to the subject
to do a portrait like that. You have to stop down that much just to keep
the whole face in focus! Problem is, at f45 diffraction limits a lens to
about 10 lines per mm resolution! At f32 you get more, but I can't
remember the number. Its not high compared to our 35mm format lenses that
give 50 l/mm at most apertures they come with! The extremely large film
captures enough detail, even with such low lens resolution to beat the
hell out of 35mm or medium format and their sharper lenses. That is why
you get that smooth but detailed look!


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Chris Crawford
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On 11/4/11 6:56 PM, "Moose" <olymoose@xxxxxxxxx> wrote:

>There are cyclical discussion threads here about the 'drawing'
>characteristics, expressed in many ways, of various
>lenses, old and new. And, of course, lots of individual comments on bokeh
>in individual posted images.
>
>At the Boston MFA recently, I saw an original print of one of the most
>reproduced photographs of all.
><http://iconicphotos.wordpress.com/2009/07/31/winston-churchill-by-yousef-
>karsh/>
>
>The value of the old portrait lenses on LF is immediately apparent. On
>about a 2x3' print, maybe bigger, the detail and
>clarity in the face is excellent, but entirely without any edginess,
>somehow both smooth and sharp at the same time. The
>smoothness of both the transition into OOF areas and the smoothness of
>those areas is exceptional.
>
>I wonder if ANY lens designed for 35mm of smaller format can create such
>an image. Certainly none I've ever used nor any
>images I've seen posted here or elsewhere on the web.
>
>LF also means no noticeable grain in a large print.
>
>Moose
>
>-- 
>What if the Hokey Pokey *IS* what it's all about?
>-- 
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