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.
Mount your camera on a tripod and get it set up, including attaching the remote shutter trigger. Set the lens to manual focus and the lens focus to Infinity. This setting, combined with the small aperture, gives you a huge depth of field.