Hey 50D RAW community!
I was the guy who brought up those ugly aliasing+moire pictures some time ago )) and even was referred to as a "moire gang" man )) so I continue to explore into the issue.
Let me tell you I love my ML'ed 50D. But the issue of aliasing (whenever I some fine details / textures fall into the frame) still bothers me. And I try to find ways of workaround.
According to the theory, the problem happens when the fineness of the details in your frame comes close to the distance between the most near pixels. In the case of 50D, it's 0.0140783 mm. Rough (and over-simplified) solution is to blur the image in those small details while keeping larger details intact.
What do I do?
First, I use the aperture values out of the sweet mid spot of a lens. Basically it's either wide open or completely shut.
Secondly, I use some old manual lens (a guy in Ukraine does Canon EF mounts for old Olympus and Minolta lenses) and they lose some sharpness.
Thirdly, I use a stills photography Cokin add-on and insert a cheap Chinese ND2 filter in front of my lenses to lose some sharpness.
There is yet another method -- to de-focus your lens from the area with problematic details.
And I'd like to suggest one tool to make this de-focusing slightly more scientific.
It's a free application for Android that I wrote last winter. It does 2 things:
- calculates DOF (nothing special)
- calculates the degree of blurriness out of DOF
It gives a specific parameter that is called "Min Detail" that shows how much any object is blurred that is out of DOF (that is, de-focused). So whenever you have fine details / fabrics make sure that you take exact focus from that and that Min Detail parameter for that distance is not less than the real size of a detail / pattern unit.
Will not go into detail here more, as I'm not sure if a lot of people will find this usefull...
The app is here:
https://play.google.com/store/apps/details?id=net.kadru.dev.visualdof2The help info is here
http://dev.kadru.net