I always shoot at 24p but yeah, 1/50 is fine. Let's hope a 1/48 shutter speed will quickly become standard in dslrs!!
I don't want to bother you with that but did you have by any chance the time to do another quick test with the lens at f4.0 and the Tiffen BD#3 ?
Here ya go! Contax 28/2.8@2.8 this time. Trying to test this lens out a bit more.
No Black Diff (Click for PNG)

77mm Black Diff 3
