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.
Step by step: 1  Set your camera on a tripod. 2  Set the camera to M (manual mode). 3  Set focus to manual with focus set to infinity. 4  Set focal length to 16mm or use the 35mm prime.5  Set aperture to f/3.5 or f/1.8 depending on which lens. 6  Set shutter speed to 20 or 10 depending on lens.7  Set ISO to 3200. Set your camera on a tripod. 2  Set the camera to M (manual mode). 3  Set focus to manual with focus set to infinity. 4  Set focal length to 16mm or use the 35mm prime.