Originally posted by tonyzoc The OEM grip/extension has a silver metal plate on the bottom and there are edges on each side similar to a Manfrotto quick release plate. I'm 99% sure that plate is designed for a quick release system...maybe it's Pentax proprietary?
When you posted I went and found pictures since my grip wasn’t with me at the time. The pictures do make it look like a quick release but it isn’t. I grabbed my pz-1 which has the Fd grip on it and carefully examined it. My conclusion:
If there’s a way to use it as a quick release; I wouldn’t trust it. The edges of the plate don’t stick out past the plastic except for a tiny amount on the left and right. The plate is very thin, there are no bevels, it’s a flat steel plate sitting on a plastic grip. The bevel appears to be designed as a cosmetic and structural component. The bevels appear to smooth the transition to the rest of the grip and avoid leaving gaps where your hands might catch on the grip. They also likely increase the contact area of the plastic to the plate.
I’ll also add that every past discussion and description I’ve read suggested nothing about this being a quick release plate. If it is one, it’s super obscure and it would be much simpler to add an arca plate to the grip using the tripod socket. Remember also this grip was designed with a hand strap and the socket was there to use infrequently since the strap was the main purpose of the grip.