No doubt you have benefited from the (Tm) Olympic Grade 5 Minute Miracle Exercise Machine, operated 5 minutes a day from your TV couch, that has enabled you to do handheld bird-in-flight shots. After all, that lens has to weigh a LOT. Do you know if B&W, SinghRay, or Lee makes the 571mm diameter CPL? Naah, surely they must have a drop-in CPL for the lens.