Archived posting to the Leica Users Group, 1999/08/30

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Subject: Re: [Leica] Seeing vs photography (was: BOKEH of 35mm lenses)
From: "Dan Post" <dwpost@email.msn.com>
Date: Mon, 30 Aug 1999 11:28:22 -0400

Mikiro-
I had assumed that most if not all animal lenses, including humans, were
aspherical. When my daughter had the lasek surgery, it was explained that
the correction could not be perfect because the way the cornea and lens work
together, and shaping the cornea doesn't alter the way the lens moves.
In the human eye the lens thickness and the resulting sagitta of the
surfaces is due to muscles making the lens thicker or thinner! Unfortunately
we can't yet mimic that in a camera lens!- imagine the possibilities of a
'flexible lens that could be focused merely by applying pressure to the
periphery!
My readings in perception seem to indicate the eye and the retina have a
point to point correspondence to areas in the visual cortex, almost as if
there were CCD's in the brain that are hooked to individual rods or cones-
like having ccd sensors remotely wired to the recording device... it seems
the eye and brain almost works like a digital system, but with a resolution
unmatched except in film!- of course the brain provides what some printer
manufacturers call (resolution enhancement!)
I think it would be very interesting to know if Leica uses any biological
research, or actually test subjects on which their optical systems are
tested- possibly they can, with the help of computer modeling, examine the
'virtual' bokeh of hundreds of formulae, and pursue only those that have the
possibility of making an image that is 'pleasant to the human eye. I almost
would bet the rent money on it! They come up with so many innovative, and
good designs, that they must use some sort of testing with actual images to
arrive at these lenses!
Perhaps they have found out what makes a 'pleasant image and can add it to
ANY formula!
(Stolen alien technology notwithstanding!)
Dan
- - slowly chipping the 'scales' from my eyes!

- ----- Original Message -----
From: Mikiro <arbos@silva.net>
To: <leica-users@mejac.palo-alto.ca.us>
Sent: Monday, August 30, 1999 7:31 AM
Subject: [Leica] Seeing vs photography (was: BOKEH of 35mm lenses)


> Hi, Dan-san.
>
> This is an intriguing point!  Seeing and photography certainly are similar
> but at the same time very different in some aspects.
>
> Vision is a cascade of processes that is so complicated that very little
of
> it has been understood.  CCD or film mimics only part of them.  I once
read
> a book by a mathematician who simulated a computational process involved
in
> visual transduction in the retina but did not understand a single formula.
> ;-)  Further, we have just started to have some vague ideas about what our
> brains do in seeing!  Vision is a wonder.  This is what an
> ophthalmologist/retinal researcher can say.
>
> PS: As far as I know, animal lenses are aspherical.  Undoubtedly, there
have
> been some experiments of taking pictures with real human or animal lenses,
> but I am not sure if anyone has ever evaluated the quality of bokeh with
> them!
>
> Regards,
>
> Mikiro
> Strasbourg, Europe
>