http://www.dalsasemi.com/news/news.asp?itemID=252

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

Want resolution? Have I got the cameras for you!

http://www.gigapxl.org/ Digital
http://www.cliffordross.com/R1/R1-detail.html Film
http://www.superlarge.com/ Film

On a more serious note, I use extremely upper high end digital cameras for mapping. Camera systems cost a few million bucks. The digital imagery is better than film in terms of geometry. But the digital spectral response is still nowhere near as rich as film. There is just no way that 3 discrete bands are capable of superceding the tremendously complex and rich spectral response of film. But what digital lacks in response it sure gives back in consistency.

I figure that we're at least 2 generations of advancement before digital color is competitive with film color. Maybe more in the NIR wavelengths.

FYI.

Back in school I got to work with 5x7 and 8x10 view cameras. They offer a subtlety of tone that is tough to match. Wish I’d had the opportunity to use that equipment for landscape work, but it was the prof’s personal property and he wasn’t gonna part with it. I remember he said he’d never taken either camera out of the studio. Of course, as images of the cameras used at both Busch’s & Ross’ sites will attest, you need a lot of hefting ability to get those puppies around. Not exactly ideal for a back country excursion unless you have a willing team to tote it all for you.

Anyway, would you elaborate on what you mean by spectral response? The digital imagery I’ve seen which is in the mere 20 megapixel range, while having been pushed through Photoshop prior to printing, is the equivalent of medium format film, at least as far as my eyes can tell.

Thanks for the links. I came across the gigapixel site a while ago

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

I'll see if I can find some links. IIRC Kodak used to publish graphs of photoreactive pigments. What you'll see is that the response curves are continuous but mostly nonlinear and indiscrete over the visible spectrum. With digital cameras the response curves are linear, discrete, but discontinuous.

In film, the same color signature can be derived from several different photochemical processes, resulting in confusion of signature classes. This does not matter for the overwhelming majority of applications. Nobody cares whether the violet of Liz taylor's eyes is due to this or that layer of photoreactive chemicals on the film. The emulsion responses are continuous over broad wavelengths, resulting in a near-infinite possible colors. but since the ability of the human eye and mind to discriminate colors is far more limited this is usually not significant.

In digital cameras the responses are discrete. Usually an RGB-type signal. There are some portions of the visible spectrum that are undetectible by the camera. It rarely matters because the lost spectrum is usually indistinguishible by the human eye. A full and complete spectrall capture would require a huge array and in the overwhelming majority of cases, nobody would give a damn because nobody could tell.

As an example, let's say I take a 35mm slide picture and scan it at the equivalent density to a comparably priced, upper-end digital camera of your choice. If you display the two pictures on a screen at the same size, you'll be hard-pressed to see a difference. Now we go back to the film and scan it at the limits of resolution of the film, say 15 microns. You end-up with a large file compared to the digital camera. Let's resample the digital image to 15 microns.

When you put them up on the screen at "normal" resolutions they are indistinguishable. If you magnify both to 8x the digital camera image will pixellate while the 35mm probably wont.

Linkey no workey. Will have some questions about the other topics later - am off to one of the local hill tops.

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"