I've been out of Singapore for a while, and wanted to try out ND filters with the possibility of stacking with GND. As this would most likely be with a UWA lens, the possibility of vignetting is quite high, so what are my options? The lenses would probably either be the 17-40 or the 24-105, both of which have filter size of 77mm.
I've seen/heard of Corkin. Any other options?