Dave, Take a look at these links: Try to avoid to skimp on filter quality and size. The Z-Pro-sysytem may be limited to 20mm FF.
http://community.the-digital-picture...hlight=filters
http://community.the-digital-picture...hlight=filters
http://community.the-digital-picture...hlight=filters
http://community.the-digital-picture...hlight=filters
Rich