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.
My long lens is the 500L f4 with which I use a 3 series Gitzo tripod and a Wimberly II gimbel head. The tripod has no center column and is sturdy as a rock. The gimbel head makes the 500mm lens glide and move effortlessly, I can literally move the camera and lens with one finger, let go and it maintains it's position.