Just discovered by using a generic 77mm rubber lens hood, trim off the hood leaving just the band surrounding the threaded ring. Wrap aroung with electrician tape for a snug fit inside the hood. The height of the ring should be covering just the corners of the petals-hood w/o vignetting even @12mm. Now, add on the 77mm filter, and the front element will be touching the filter @13mm w/o vignetting. Compare with the original 82mm filter adapter, vignetting start at about 18.5mm on 1D. Any 1D users interested can also try this on their 15-30 because of the same inner diameter of the hood, the height of the ring can be adjusted by add on an extra 77mm filter ring.


Regards,
Wilbert Chan