What is image stabilisation?
Image stabilisation is designed to help you capture sharp images at a slower shutter speed than you would normally take images. Camera retailer, Clifton Camera explains:
You can estimate the speed that you need, using an old guide, so that you can avoid potential blurring when you’re using a hand-held camera. All you need to do is select a shutter speed that’s at least the reciprocal of the effective focal length of the lens that you’re using. So, if you’re using a 100mm lens, you need to use a shutter speed that’s at least 1/100sec on a full-frame camera – or 1/150sec if you’re shooting with an APS-C format camera.
When your camera or lens has image stabilisation built-in, it is usually possible to shoot at lower shutter speeds to avoid blurring. Most manufacturers quote an extension value, often 3EV, 4EV, 4.5EV or more. For every EV or stop quoted you should be able to halve the safe-shutter speed, but bear in mind these tests are done in lab conditions and you need to find your own limit.
The first stabilisation systems were built into the lenses because they were originally designed for photography and were developed with film in mind. A stabilised lens has an element or group of elements that can be moved to compensate for those tiny movements that you make as you hold a camera
When turning off the stabilisation on telephoto lenses like the Canon EF 70-200mm f/2.8L IS II USM you’ll see much more shake through the viewfinder.
The Olympus OM-D E-M1 II’s hybrid stabilisation system is so good that with wide-angle lenses some photographers are able to take hand-held shots, with shutter speeds measured in seconds. It’s also extremely useful when you’re shooting video hand-held.
The speed, direction and size of any movement in the frame is detected by movement sensors, which shifts the stabilisation element to compensate and keep the image of the subject at the same point on the sensor or film frame, thus reducing blur. Canon, Nikon, Panasonic, Sigma and Tamron all produce stabilised lenses.
A lens-based system is perfectly suited to the focal length of the lens in use so that it’s able to make the large corrections that are required with long telephoto optics.
Cameras with sensor-based stabilisation have the same type of movement detectors as a stabilised lens. However, sensor shifting, or in-body image stabilisation (IBIS) is when the image sensor is shifted instead of the moving the lens. Cameras with sensor-based stabilisation have the same type of movement detectors as a stabilised lens.
Brands that have been the main exponents of sensor-based stabilisation are Olympus, Pentax and Sony. The benefit of an in-body system is that it can be used with any lens that can be mounted on the camera.
Olympus, Panasonic and Sony have started to use lens and sensor-based stabilisation together to create hybrid systems that have far greater stabilising power. The benefit of a hybrid system is that it combines the useful effects of both systems and the camera can choose type of stabilisation to use for any given situation. It can also correct a wider range of movements, with 5-axis no being typical.