Vertical Control Grips
A vertical control grip is generally a type of battery holder or battery pack that can attach to the bottom of a film or digital camera. However, some grips don't hold batteries. Many grips have a vertical shutter button and other camera controls, dials, and focusing apparatus to let you take vertically oriented photographs a lot easier. A good vertical grip should be compact, lightweight and ergonomically designed. It should also give you extended battery power and a tripod socket.
Vertical grips come in various shapes, materials, designs and sizes. A rubberized outer surface is the best as it will enable you to get a good grip of the camera. Most grips will offer you several battery power options. They range in price from about $30 to several hundred depending on the features, the material it is made of, the brand and the model.