Shield is a European manufacturer of red dot sight and optic mounts. They are the OEM manufacturer of the JPoint Reflex Sight, Trijicon RedDot and Tasco Optima sights. The company has developed a mount for their red dot sights which allow them to be mounted on digital cameras. The mount attaches to cameras via the Hot Shoe mount point that is normally used to attach flash units. It does not obscure the camera’s optical viewfinder.
I am not a photographer but I assume this would be useful for sports photography or other situations where speed is required.
Many thanks to Dom for the photo.