The D/Focus Systems D/Support Lens Support is a simple, height adjustable, lens support for SLR lenses. It uses a single 1/4-20" screw and Velcro strap to provide an additional point of stability for your camera / lens. DSLR cameras typically only have one mounting point. This can be problematic when using a follow focus because the lens will want to shift while focusing, even with a very sturdy baseplate. This issue is especially problematic with long, telephoto lenses. The D/Support can help prevent this "image shift" by providing an additional mounting point for your camera / lens combo.