The Markins quick release L-bracket LN810 fits the Nikon D800/D810 without MB-D12
Custom fit with dedicated design for Nikon D800/D810 (Won't fit the MB-D12 grip.)
Made of highest quality duralumin.
Hand strap hole.
Scratch resistant hard-anodized surface.
Safe and ergonomically rounded corners and edges.
Extra 1/4" hole for a monopod.
Compatible with other major manufacturers' Arca-Swiss style
Comes with a wide headed 1/4"-20 screw (HB1.)
" Get an L-bracket
If you area keen tripod user, an L-bracket can make a massive difference. It allows effortless switching from horizontal to vertical framing, keeping all the weight on top and the lens in the same position. It´s far better than flipping the head 90 degrees, which can seriously unbalance the tripod and compromise stability"
(Article from Advanced Photographer UK)