Photographer Guillermo Luijk offers an intriguing look at the possibility of noise-free digital images from any camera that offers RAW files. The technique consists of combining multiple frames taken at up to +4EV (using his software program). Although I’m reasonably happy with the noise performance of newer cameras like Canon’s EOS 1D Mark III, the possibility of richly-detailed and noise-free dark areas opens up new avenues for exploration, especially with inexpensive consumer-grade cameras. I’m a little concerned about non-linear color accuracy with changing exposure, but perhaps color will be superior.
What’s frustrating to me is why this stuff isn’t just built into the camera as a mode (tripod required) which takes the 2 or 3 or 4 or N images and produces a single outstanding RAW file. The idea is in the same vein as multi-shot medium format digital backs, which shift the sensor up/down/left/right by one pixel to effectively achieve true RGB color without interpolation. So far, Nikon has done the most in this area (not very much), offering multiple exposures in-camera with the D2x and D200, while Canon has done nothing at all.
There are all sorts of goodies which could result from the combination of multiple frames: near-zero noise, 32-bit dynamic range (HDR), increased sharpness (Photo Acute), depth of field, etc. Though some such applications are now just emerging (as software programs), all of these features and more will eventually be built into the camera. For that matter, why not just design a sensor that can take additive exposures until a noise-free image is obtained with 32-bit dynamic range? Time will make it happen.