RE: filmscanners: Digicams again was Re: filmscanners: Minolta DiMAGE Scan & Dimage 7 camera

[rafeb <rafeb@channel1.com>]

At 07:42 AM 6/30/01 -0600, Frank Nichols wrote:
>Robert,
>
>I understand your hesitancy, however, you make several assumptions that I
>didnt.
>
>1. SNR remains at todays levels.
>2. Sensitivity remains at todays levels.
>3. The array would be small - why not a 4" x 6" with a 10x increase in
>density? that would require about 1.5GPixels (If I didn't slip a decimal
>point.) Or even an 8x10?
>
>In RAM/CPU technology - a simliar technology - the increase over the years
>has not just occurred in dimensions, but in performance (speed), power
>requirements, etc.
>
>I will stand by my prediction and be here in 5 years to say I told you so!
>:-)


The improvements in silicon technology are mostly 
improvements in lithography (smaller features, 
enabling higher densities) and placement of dopants 
in the silicon (in all three dimensions) via ion 
implantation.  Also, better ways to clean up after 
masking steps, using plasma etch instead of wet 
chemistry.

There really haven't been that many revolutionary 
developments in silicon -- mostly evolutionary.  
At the silicon level, you're still moving electrons 
and holes across junctions and through FET channels.

>From time to time, folks figure out clever new 
technologies that simply make older problems 
irrelevant.  Delta-sigma A/D converters come to 
mind.  There was a time when all A/Ds used resistive 
networks, and these created an inherent upper-limit 
on resolution (around 12 bits.)  Newer A/Ds simply 
scrap that approach to achieve real resolutions 
of 16 bits or more (at high sampling rates) or even 
up to 20 bits, where bandwidth is not an issue.

In terms of CMOS or CCD sensors, I remain convinced 
that they need to be physically larger before they 
become interesting to some of us "purist" photographers.
That may yet happen, but only if yields improve.  Or, 
alternatively, firmware steps in to deal with the large 
number of defective pixels.


rafe b.