Paul,


Cokin X-Pro uses 5 1/3 x 6 2/3 in (130 x 170mm) filters. Recommended focal lenghts 15mm on full frame (10mm on APS-C) and up.


Cokin Z-Pro uses both 4 x 4 in (100 x 100 mm) ND and 4 x 6 in (100 x 150 mm) ND graduated filters. Recommended focal lengths 20mm on full frame (13mm on APS-C) and up.


The Cokin filter holders will take Cokin