Ignorant question about sharpening and the 7D!

Image sensors without a low-pass filter in front of them are sensitive to moire, when pictures are taken of certain subjects. Hence the camera manufacturers usually place a low-pass filter in front of the sensor. That filter takes away "the edge" of the sharpness the sensor is really capable of, but also combats moire. The 7D's low-pass filter is a tad more aggressive than most, which in turn means that images that come un-sharpened out of the camera look a bit dull.

To get back some of the lost sharpness we have to re-create it, from the now moire-free image, by applying some sharpening in post processing.

One can become very technical here, but perhaps this short summary is what you were looking for?

--
Anders