Originally posted by Clavius I was told that all an AA filter does is blur the image slightly to prevent moiré effects when shooting grids, fences and such. Blurring can very easily be done with software, either in the camera body or in PP.
That's wrong. Even the term AA filter is technically wrong.
What happens is a necessary spreading of color information
prior to Bayer filtering. If not done, color information is destroyed forever and cannot be recovered. It can't be done electronically to the raw data either because a red sensel cannot capture the information of a blue sensel.
What people call moiré pattern actually is a so-called false color moiré pattern. Sensors with a microlens array produce no classical moiré artefact.
All you can do is to try to detect the false color moiré pattern after the fact and desaturate it. However, this step desaturates parts of the image and destroys detail too.