What ND filters

[smiller]

I think the PP Shutter series (ND only) can use the stock gimbal lock, it is the Vivid series (with polarizer) that don't work with the gimbal lock (unless it is modified.)

I have to correct myself here, I just received a set of the PP Shutter ND filters and they are just a tint bit too long for the stock gimbal clamp to work without some modification. I think the best option is to remove the tab at the read of the clamp so that you can retain the lens protection. Also I weighed the PP Shutter (ND only) filter and it weights 4.2 grans, vs. the stock UV at 2.4. It seems unlikely the additional 1.8 grams could matter. At least the PP seem to be real glass as the stock UV filter element seems to be some kind of plastic.