True! The ZF mount lenses are normally $200-$300 cheaper because of the non-electronic mechanism. Optically is the same as that of ZF2 or ZE versions. I am using the ZF 18mm on my Canon body with the use of an adaptor.
Get the Nikon Mount . more versatile as can use on either Cameras with adapter.The Nikon ones always sells out at retailers.My 15 and 135 are Nikon Mts and 100 and 35f1.4 Canon.