Do you need to support a very long lens with mattebox and maybe a rain deflector? All that weight up front will stretch the balance limits of your regular sliding baseplate.
Peter Denz’s Support Plate 600 is 600 mm (23.62”) long. It is extremely lightweight. The dovetail on top accepts DENZ BP multi and baseplates from other manufacturers. A DENZ lens support, DENZ support slide or DENZ Ø 19mm Deluxe Carbon Fiber support rods can be mounted as well. All of these can slide onto the plate from the front or back, protected by push button safety stops on both ends. The bottom side of the plate has two moveable sliding blocks with mounting threads for quick release plates. Side-loading is compatibel with OConnor fluid heads. This Support Plate is highly recommended for the larger Angenieux, Alura, and Fujinon Premier zooms along with Nikon, Canon and other fast telephotos.
Denz’s Lens Support Plate 325 is 325 mm (12.79″) long. www.denz-deniz.com