Canon dust mapping for 1DIII

[Khurram]

I had some questions regarding the dust mapping on the 1DIII.

1.  has anyone tried it and is it effective???
2.  The instructions don't seem that practical in the field (i.e. stop down to F22,
      set the focus to infinity, the focal lenght to greater then 50mm and aim the
      camera at a solid white object that is less then 2 feet away.  Finding a solid
      white object without any patterns is kind of hard in the field, I thought about
       just aiming at the a clear blue sky, but haven't tested yet.
      Has anyone tried any other way to map the dust data and is it effective???

[madmanchan]

Part 2 isn't intended to be used in the field. You can do that part at home.

[Khurram]

Part 2 isn't intended to be used in the field. You can do that part at home.
[a href=\"index.php?act=findpost&pid=137249\"][{POST_SNAPBACK}][/a]

Eric,
does it really help doing the dust mapping at home?  If the auto sensor cleaner moves dust to other locations, does it really help doing mapping at home?  Have you tried the effectiveness of the mapping?  I'm trying to get some feedback on how well the mapping works.  I did try it once with the xti, but didn't really notice much difference (although i didn't really give it much of a chance either).

[djgarcia]

I find the sky works fine as a dust mapper background.