gold ring, but they still have the word "Ultrasonic" printed on the lens barrel. Stepping motor Canon announced Stepping motor (STM) lenses first in June 2012, alongside the EOS 650D/Rebel T4i/Kiss X6i. Canon stated that this technology allows smooth and silent autofocus, and with compatible bodies (the first of which is the 650D) will provide continuous autofocus in live view and video. Unlike USM, STM lenses use focus-by-wire to enable full-time manual mode. Two main disadvantages are linked to focus-by-wire: First, the need to computationally process the input before the intended action is executed leads to a sometimes perceptible lag. Second, using the motor requires power, so when an STM lens is not connected to a camera or the camera is switched off, changing the focus is impossible. All stepping-motor lenses are marked with the letters "STM" on the front of the lens as part of the model designation. Image stabilizer The image stabilization (IS) technology detects handheld motion and optically corrects it. It only corrects handheld motion; if the subject of the photograph is moving, IS will not stop it. It also can only stabilize so much motion, ranging from two to five stops, depending on the specific IS in the lens. Canon has released several versions of the IS system, including the following: The first version, first used in the 75-300mm lens (1995), takes approximately one second to stabilize, provides approximately two stops of stability, is not suitable for use on a tripod, or for panning. The 300mm 4L IS USM lens, released in 1997, adds IS Mode 2, which detects whether panning is taking place horizontally or vertically, and only compensates for vibration in the plane perpendicular to the plane of panning. In 1999, with the release of the IS super-telephoto lenses (300mm 2.8L through 600mm 4L), tripod detection was added, so that the lens could be used on a tripod with IS turned on. In 2001, a new version of the Image Stabilizer was created for the 70–200mm 2.8L. This version takes approximately 0.5s and can be stabilized up to three stops. In 2006, the 70–200 mm 4L IS USM was released with an Image Stabilizer which allows up to four stops of stabilization. In 2008, the 200mm f/2L IS USM was released with a new version of IS which allows up to five stops of stabilization. In 2009, the 100 mm 2.8L Macro IS USM