Oh, by the way: I used a regular (i.e. non-wide-angle) Hoya CPL 77mm on my 17-40 and never got any vignetting. Only on the 10-22 it would show.
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EOS 5D|EOS 600|15-30|24 1.4 L|135 2 L|2x 580EX|2x CP-E3|ST-E2|2x Pocket Wizzard Plus II|IXUS 850IS|Crumpler|Manfrotto|
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