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.
2984Views 447Downloads Found in Physics & Astronomy. This allows a red dot finder scope to be mounted on a DSLR. Tested on canon. This should allow astro photographers centre objects when using conventional lenses. Possible future improvements would be to include a dimple to locate in the hot shoe, but the frictional resistance seems adequate.