ole sarg wrote:
I don't remember sharpening in the dark room. Are film cameras or film sharper than digital? Was manual focus better than AF now available with digital?
@Ole, the reason you never "sharpened" in a darkroom is because there is a fundamental difference in the way images are recorded on film or digitally.
With film, each "pixel" (though that is not an exact term in the analog world) has chemical elements that record the three primary wavelengths of light. Surely you remember seeing diagrams of Kodachrome et al showing the layers that record each set of wavelengths. So at any one tiny section, say 1x1 micron square, there is a latent image containing elements of the three primary colors.
With digital (except for the foveon sensor found in Sigma's DSLR) the chip can only measure light intensity (i.e., black and white for all intents and purposes). When you see the specification that a CCD is 3000 x 4000 = 12 megapixels, that means the chip has an array of 3000 by 4000 photo sites, but again, each individual photo site can only register light intensity.
So, the way color digital chips work (again, except the foveon) is by having a tiny filter placed above each photo site in that matrix. The typical Bayer array format has 1 red, 1 blue and 2 green filters over each 2x2 square of photo sites. (There are 2 greens because human eyes are more sensitive to green). What must happen to this data is a calculation where the combined RGB color value at a given pixel is calculated depending on the light intensities at surrounding photo sites. This is why there is no such thing as "seeing" a RAW file - it is purely the values collected at all of those sites, but without the interpretation of the file converter that's just a bunch of numbers. So the computer in a digital camera does those calculations so you can "chimp" on the back. And if you import a RAW file to a computer and convert it with different software you could see different interpretations.
Because of the repeated 4x4 matrix of color filters there can be a problem with "jaggies" in certain scenes; thus the anti-alias filter is usually layers on top of the color filter layer. However, the Nikon D800E does not have the AA filter. And the Fuji X-series cameras that use their proprietary X-trans CCD use a different array instead of the Bayer which is said to eliminate the problem and thus make the AA filter unnecessary. With the former, it is said to be more likely to lead to moire effects with certain subjects; with the latter the IQ is pretty outstanding since Fuji avoided that simple repetition of color filters with a staggered 6x6 array.
Still, since each final site must be calculated based on the readings at adjacent sites with the other color filters on them, there is a certain loss of sharpness that might need to be countered with the sharpening process.
Now, I haven't played around with the Leica M - but what they did was leave the CCD unadorned - there is no Bayer array of filters atop the photo sites - so it is purely a B&W camera. And my money says that since there is no need to interpolate colors at each pixel but rather just take the straight readings from the CCD, there is no need to sharpen an image from a Leica M (at least not until it is enlarged by many times).