I read through the recent addition to the site on understanding split ND filters. A pretty good intro I thought, but there was no real explanation of hard vs. soft grads that I saw, no mention of how to avoid having a dividing line when using a hard split filter (hand holding and slightly jiggling the filter works), no mention of Singh Ray filters (just Cokin and Lee), and no mention of the Singh Ray 'reverse' grads. Most graduated filters (soft) are clear for 1/2, then gradually go from clear to darkest at the top of the filter. The Singh Ray reverse grads are clear on the bottom, but the top half is reversed so the darkest part is at the center, and clearing toward the top of the filter. Why would you want one? Let's say the sun is right on the horizon, sunrise or sunset, and the clouds above are less bright than the sunlight below them.