Xenedis's ND Filter Shutter Speed Cheat Sheet

[accesser]

Ok possibly a stupid question does this chart only apply to non gradient ND filters?

[Xenedis]

Ok possibly a stupid question does this chart only apply to non gradient ND filters?

It's intended for non-grad ND filters, but the mathematics applies equally to the filtered portion of a GND filter. It's probably less useful for that application, as GNDs are almost always used to even out the exposure between land and a much brighter sky.