TAKO. INTERNET SEIT 1996.
Olympus-OM

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

Subject: Re: [OM] Lens design, bokeh, etc.
From: "List, OM" <om-list@xxxxxxxxxxx>
Date: Fri, 4 Nov 2011 18:24:25 -0700
Karsh is reported to have often used Kodak Commercial Ektar lenses  (a 14"
/ 360mm being one of his favorites) ... they have a very good reputation.
http://www.sciencetech.technomuses.ca/english/collection/karsh5.cfm

Wide open would have been f6.3. Some Kodak lens test results (shorter not
commercial Ektar) can be found at:
http://www.hevanet.com/cperez/testing.html

f45 seems too stopped down. f22 or more open would seem to me to be more
likely. Many of the portrait lenses have relatively open apertures (f4.5
for heliar's or Kodak Portrait) and are used relatively wide open, more so
than landscapes. A heliar is considered to loose its special
characteristics by the time it is stopped down to f16.

Jeff Keller

On Fri, Nov 4, 2011 at 4:16 PM, Chris Crawford <chris@xxxxxxxxxxxxxxxxxxxxxx
> wrote:

> 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!
>
>
> --
> Chris Crawford
> Fine Art Photography
> Fort Wayne, Indiana
> 260-437-8990
>
> http://www.chriscrawfordphoto.com  My portfolio
>
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>
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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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>
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