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.
The focusing method used when looking through the viewfinder, not the LCD. In the Canon T4i when you focus through the viewfinder you use what I call the big brains of the camera and the focusing method used is called Phase Detection. So how does the two new STM lenses compare with a USM. Real Quick Definitions.