[BasilG]

For what it's worth: I've just reproduced the effect with my own camera and that test chart. My conclusions are: (i) the zero contrast rings move according to the amount of defocus, and (ii) there is contrast inversion across each ring.

 

http://forum.photozone.de/index.php?/gal...hart-shot/

 

Download the test chart here:

 

http://diglloyd.com/blog/2014/20140416_2...ation.html

 

and try it for yourself.

 

I don't quite understand why you say that phase doesn't contribute - you need amplitude and phase contribution for image formation, no?