One aspect of most digital camera sensors (I think the only exception is the Foveon chip) is they all use some form of color separating filters on a black and white sensor, creating a color matrix. In other words, no digital camera sensor provides RGB separation per sensor. The sensor is only used to determine R G or B levels (or in the case of some Sony lenses two different greens). They still bias to the green accuracy.
To explain further, a standard scanner, flatbed or dedicated uses some form of tri-color CCD strip (or in Nikon's case, a black and white CCD with changing LCD back lighting). Ever single location that is scanned is done so by three unique sensors (other than Nikon again, that uses another approach to get to the same place), R, G and B. So every location that is read for measures R, G and B content or color separation. That is not, however, how digital cameras operate. Digital cameras sensors are mainly some version of the Bayer pattern matrix over a black and white sensor. The typical Bayer matrix is as follows: RGRGRGRGRGRG GBGBGBGBGBGB RGRGRGRGRGRG GBGBGBGBGBGB R = a red filter B = a blue filter G = a green filter So any one location on the sensor grid is only color separated for one primary color. That sensor has no idea how much of the other primary colors exists, only luminosity. You will also note that in this basic form, 25% of the sensor locations separate for Red and the same for Blue, and 50% separate for Green. Then sophisticated, but still inaccurate, interpolation schemes are used to fill in the blanks. Other electronic filters are used to try to screen out further errors, and do so with relative effectiveness, but still color resolution is not what it is on a flatbed or dedicated triline CCD. There is no simple way to overcome this limitation, and it also explains why a digital camera sensor can capture an image so rapidly, while a scanner takes considerable time. I suppose, just like with digital camcorders, as prices continue to drop on CCDs, eventually a tri chip still camera may come about at reasonable price, but for now, most if not all (other than the Foveon) that are available to the general public have this limitation. I would guess that reproducing an analogue form like film which has randomized dye clouds of colors might even further confound this matrix grid approach. So, while a "digital copy camera" may be a good quick answer for non-mission critical work, the triline or similar CCD approach has some advantages that aren't easily resolved with digital cameras today. Art [EMAIL PROTECTED] wrote: > Is the technology to the point yet where we could use a high quality > duplicating lens and a high resolution digital camera (Canon/Nikon 12-16mp) > to digitize slides and negatives. What would the potential pitfalls be? > Would Vuescan work to color correct the negatives? > > Forgive me is this subject has already been discussed to death. I've been > away from the list for a few years. > If has already been addressed someone please direct me to the archives. > > Thanks > > Bob Kehl > ImagesByKehl.com > online for four years - thanks to this group > > ---------------------------------------------------------------------------------------- Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body