Originally posted by Christine Tham PS - I don't believe the AA filter can be "undone" by sharpening. Any more than a Nyquist filter can be "undone" by transient processing in audio. If you don't like AA, buy a camera without.
This is why I made my statement.
I know this isn't the thread, so I make a long story short:
1. Bayer AA filters are no Nyquist filters. They leave about 10-30% contrast around the Nyquist frequency.
2. With an excellent lens, the remaining overall contrast at Nyquist is still well above zero, say above 5%.
3. With a low enough ISO floor (K-5 ISO 80 is perfect), the AA filter then can and should be undone (no zero point in the MTF curve between 0 and Nyquist).
4. The undoing is best done with deconvolution. LR3 detail slider selects deconvolution if pushed to the right.
5. The problem is that with
additional sources of blur or noise (defocus, lens, diffraction, shake, motion, haze, high iso etc.), the AA filter can't be undone indeed and wasn't necessary in the first place.
Personally, I like AA filters. They avoid color Moiré artefacts which can ruin an entire image. And if used properly, don't necessarily reduce the available resolution.