Common skin warts (also called cutaneous warts) are raised round or oval growths. A wart may be lighter or darker than the skin around it. Some warts may have tiny black dots in them, often called seeds. The dots are small, clotted blood vessels. Warts may occur alone or in larger groups that merge and form patches.
According to Canon (link):  Canon addressed the âfeedback loopâ in later model IS lenses by introducing an algorithm to the IS detection system to automatically recognise when the lens is mounted to a tripod.
Most new photographers understand what a tripod is: a set of legs that can be attached to the bottom of your camera body or the bottom of your lens to support your gear while you shoot. However, many beginning photographers misunderstand why having a tripod is very important.