Digital BW, The Print

Hi Jerry,

Having said that (below), I thought I should find out how many 'megapixels'
our eyes have!

It seem that in 'digicam advertising jargon' our eyes are pretty good - 126
'megapixels'. So our cameras have got a way to go yet!

We have 120 million rod sensors in our eye that are not sensitive to color;
they only measure luminosity. The cone sensors only number about 6 or seven
million, and exist in three types which sense red, green, or blue. Their
proportions are quite different to a camera; we have about 64% red, 32%
green, and only 2% blue sensors. Most of these color sensors are located in
the centre of the eye - the fovea centralis. Is this where Foveon gets it's
name from?

The cones are about 0.002mm in diam and about 30 000 are packed in the fovea
centralis which is about 0.3 mm in diam. So at a rough calculation that
gives us about 15 000 sensors per inch compared with a D60's 3000 per inch.
But of course the D60's chip is bigger than our fovea!

One analogy says that our rods are like a high-sensitivity black&white film
such as Tri-X (back on subject), while our cones are like a low-sensivity
color film overlapping the b&w film.

Bob Frost.

PS Isn't Google wonderful?


----- Original Message -----
From: "Bob Frost" <bobfrost@...>
>
> That is not to say that all interpolation is bad; after all our eyes
operate
> on exactly the same principle (I think), interpolating from the rods and
> cones in our retina that have different sensitivities to red, green, and
> blue light.