RE: [Leica] Digital back for Leica lenses

["Phong"<phongdoan@mindspring.com>]

Austin Franklin wrote:
> I have been designing digital imaging systems
> for over 25 years ;-)

Are you still ?
I have a math and software background, but have been busy with other stuff,
only recently have taken a keen interest on the topic. My interest though is
on the software side.  I can't tell a CCD from a CMOS for the life of me. 
Still I would like to learn enough of background material, because it's never
just software, is it ?

- - Phong



On Thu, 21 Nov 2002 10:56:32 -0500 Austin Franklin <darkroom@ix.netcom.com>
wrote:

> Hi Sam,
> 
> > Does that mean that we are nearing a
> threshold in CCD development as
> > it
> > relates to size, using today's format
> benchmarks? At what resolution
> > would the laws of physics start working
> against the 35mm format?
> 
> They already DO work against it.  It's a matter
> of balancing a number of
> things.  First and foremost is you pretty much
> need %100 sensor yield.  In
> other words, all the sensor elements in the
> array have to be good.  The
> larger the sensor (as in number of sensor
> elements) the higher the chance
> that some of them will be bad.  Second is
> balancing sensor element size with
> noise.  The smaller the sensor elements, the
> higher the noise.  You can get
> a lot more sensor elements per unit area, but
> you get noise images.  For
> video, that is fine, but for one shot imaging
> like photography, it's not so
> good.
> 
> > Are we ever going to see
> > 40
> > megapixel CCDs based on the 35mm format?
> 
> That's an easy thing to calculate.  Assume a
> 24mm x 36mm (864 sq mm) sensor
> array size:
> 
> 5u (25u sq) sensor elements given an array of:
> 34M
> 7u (49u sq) sensor elements given an array of:
> 17M
> 9u (81u sq) sensor elements given an array of:
> 11M
> 12u (144u sq) sensor elements given an array
> of: 6M
> 
> And 5u sensors aren't going to be that great,
> at least in current
> technology...but it certainly is possible. 
> Processes for making CCDs are
> getting better....but along with the physical
> individual sensor size as an
> issue, it's getting the wires to/from the
> sensor elements that becomes an
> issue...
> 
> > I once read that digital had
> > to
> > get to 40 megapixel to equal some of the
> finer grained 35mm films,
> 
> Well, that seems about right, but film grains
> and sensor elements are really
> different animals.  One is random in both size
> and position, and the other
> is fixed in both size and position.  Apples and
> oranges.  Plus, digital
> imaging sensors, with the exception of Foveon,
> don't have three planes of
> color...only one plane, with %50 Green sensors,
> %25 Blue and %25 Red.  So,
> don't confuse number of sensor elements with
> pixels, they are NOT the same,
> except in the Foveon, which uses a tri-sensor
> element.
> 
> > BTW: How do you know so much about digital?
> 
> I have been designing digital imaging systems
> for over 25 years ;-)
> 
> > Any good websites for
> > someone to learn the basics, something like a
> CCD Design 101?
> 
> Funny enough, Kodak.  They have a couple of
> papers on CCD imagers.  Try
> poking around their web site in the digital
> imaging sensor area, and if you
> can't find them let me know, and I'll email
> them to you.
> 
> Regards,
> 
> Austin
> 
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