Micro-contrast is another way to say "acutance" and contrast is generally a different thing, unless we want to debate words endlessly. Photographers don't confuse the two things. I personally dislike the word "micro-contrast" because it just leads to confusion. If it is acutance, be it called acutance instead of by another name. Will not smell differently, but it will be clearer.
Judging definition of a lens by an image less than 1 mp is not different than judging colour balance of a film comparing uncalibrated and not colour-managed scans. In both cases the exercise is moot.
In the first case, what is judged is the degree of "sharpening" of the image to make it appear sharp on screen (this is done by increasing acutance, by the way). In the other case, what is judged is just the random colour mistake of scanners - monitors plus the ability of the scanner operator.
Differences in lens qualities are subtle and need a much higher pixel resolution to be judged. Even in that case, a decent amount of digital sharpening improves the sharpness. Convolution-based sharpening also helps. Those interventions are necessary for a good rendition on a monitor, but insert an intermediate layer which contributes to prevent judging a lens through the web.
In one sentence: the only proper test of the sharpness of a lens is the light table and the loupe. If really a comparison must be made through the web, the maximum resolution obtained by the camera or scanner should be shown,
but the result will be, in any case, mediated by the post-processing.
The general consensus is that very fine lenses, like Zeiss and Leica, do have higher acutance than high-quality lenses by the Japanese producers. "Very good" is good but it is not up to "Exceptional". Whether one needs "exceptional" is obviously debatable and I am sure somebody will add a comment saying that art has nothing to do with resolution (which would be true and obvious).
Overall contrast in my experience normally goes with number of lens elements: the higher the lens element count, the higher the "black point" (blacks less black) so less perceived contrast (
coeteris paribus). A Tessar scheme is normally very contrasted. I like contrast. Overall contrast has nothing to do with acutance and micro-contrast should not be mentioned when talking contrast.
Overall contrast for me is the perceived distance between maximum black and maximum white. Maybe for other photographers "contrast" means something different, such as the diffusion of light from bright zones to shady zones ("flare", "blooming"). How do we define this: "local contrast", probably? Local contrast is certainly a metre of lens quality. I suppose it mostly depends from the lens coating and from the number of lenses, and the number of air-glass surfaces. It ultimately is linked to overall contrast as they both depend from how much refraction there is, and refraction depends from number of lens elements, number of air-glass surface, quality of coating, suppression of scattering light within the lens (black painting).
Overall contrast in a digital image can be and should be "optimized" by properly setting the "levels" of the image. It can also be pushed to obtain a "graphic" effect (as in this image posted by oneANT:
Dead Link Removed). If the shadows are violently pushed to pure black, and there is some very bright high lights, the effect is of great contrast. That same effect can be obtained with any lens, if you can properly use the "sliders".
Which again leads me to repeat that judging lens qualities by a 1mp digital image makes no sense.
My personal opinion is that a conversation is much more enjoyable if everybody avoids making comments about lens quality as if it was something scientifically debatable. No point in "challenging" another forum user in general, and certainly no point in "challenging" him on something which us purely subjective, adding some 1mp digital images as a "demonstration" of one's point
Please let's not transform this into another religion war: Zeiss fanatics against Canonikon fanatics etc. Fanatism is bad for photography.
