Archived posting to the Leica Users Group, 1999/10/12
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]From: Jim Brick <jimbrick@photoaccess.com> Sent: Tuesday, October 12, 1999 17:37 Subject: [Leica] Part 1: For those who think film will be dead in the near future... (extra long) > Current semiconductor chip geometry = .18 micron > It could possibly go to .1 micron. Hmm... see below. > To put things in perspective, the volume of an "average" > silver halide grain is .0000000000001 cubic cm. That's a cube that measures 0.00001 centimeters on a side, which is 0.1 micron. Hey... that's the same size as the semiconductor components you mentioned above! What were you saying about putting things in perspective, again? Let's see... these dimensions correspond to a resolution of about 5000 line pairs per millimeter. Could you point me to the lens system and film that will allow me to record image detail at 5000 lp/mm? If you can't do that, could you explain to me how the above figures are really germane to this discussion? > So now, in digital, we have 256 possible density levels ... You seem to be comparing apples and oranges. When you discussed film, you mentioned the theoretical possibilities at the molecular level, but when you discuss digital, you mention the arbitrary A/D conversion threshold for the signal in cheap converters. Furthermore, your estimate of the number of silver halide molecules in the volume of the grain you describe is very optimistic, I think. > While in film, we have a grain site that has 10 Billion molecules. They are less than ten angstroms in diameter, then? I thought just the orbit of an electron around a carbon atom was (according to you) one angstrom. How can a silver atom and a halogen atom fit in ten angstroms if a single carbon atom barely fits in the same space? > If it takes 1,000 silver atoms to produce a developed "speck" on > the film, we have 10,000 possible density/size levels producible > at a silver grain site. But a CCD can resolve 100,000 levels of intensity. I suppose your arguments might influence someone who just glances at your facts and figures, but I don't find them persuasive at all. -- Anthony