Hi, anyone know if this one and this one interchange? The (more or less) local place has the lens I want and the other filter, and as much as the obvious answer is no if they're simply a different colour then I'm not going to fuss.
Only difference is the paint color, the W and WII drop-ins are physically compatible with all the supertele lenses (the WII paint matches the MkII lenses and MkIII extenders).
Note that your post title mentions drop in polarizers, but your links are to standard holders for 52mm screw-in filters. If you want a CPL, get the drop-in CPL. The holders you linked are for ND filters (or IR, etc.), if you mount a 52mm CPL in one (assuming it's thin enough), you'll have no way to adjust the polarization without removing it (Canon's drop-in CPL has a knob on the outside that's geared to rotate the inserted CPL).
Thank you! The polarizers are the next pair of links on the page, that'll teach me to ask questions at such a late hour! Judging by the damage for it I'd almost suspect Canon thinks they have a monopoly or something...
Jim, I bought mine from UniquePhoto in NJ. I don't know if they still have the best price, but they were about $60 less than anywhere else last year. It was my first order with them, but they're Canon authorized and they shipped quick and with no issues.
I ordered my Tripod Mount Ring C (for the 70-300L) from UniquePhoto, as they were the only ones who had it in stock when I wanted it. Also my first (and only, so far) order with them, but they delivered.