[pure-silver] Re: <somewhat OT> New lens design technology
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Fri, 2 Feb 2007 17:00:27 -0800
----- Original Message -----
From: "Sauerwald Mark" <mark_sauerwald@xxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, February 01, 2007 6:27 PM
Subject: [pure-silver] Re: <somewhat OT> New lens design
technology
That is true, but for a conventional lens there is a
limit to the diameter that you can make a lens and
still maintain a given focal length, with this
arrangement, there is not a limit - as the disk gets
larger, you have more internal reflecting surfaces
(those would be equivanent to the elements in a
conventional lens), and the aperture would grow as the
square of the diameter - so a larger lens gets more
and more light gathering capability. Also, in a
conventional lens, there is a fairly large amount of
light loss from passing through the air-glass surface,
in this case the entire light path is within one piece
of glass, so those losses should be minimal - think of
how many internal reflections light has when
travelling through a piece of fiber optic cable.
--- Peter Badcock <peter.badcock@xxxxxxxxx> wrote:
By a conventional lens one ususally means one with
certain image geometrics. In theory a conventional lens can
not be faster than f/0.5 because the light rays are entering
the entrance pupil at a 90 degree angle at that speed.
However, its possible to make faster lenses by using some
other image geometry.
I wonder about the MTF for this lens. An annular ring
will introduce a filter effect causing the resolution
"frequency response" to vary considerably. This does not
mean that a high resolution lens can not be made this way
but there may be a loss of contrast at some intermediate
values. Its an extremely interesting concept.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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