What Is Image Stabilization?
Image stabilization (IS) is also sometimes referred to as vibration reduction (VR). It’s a mechanical feature on some lenses and cameras that limits the amount of blur caused by camera shake.
Generally, the slowest shutter speed you can use without IS and still get blur-free images is 1/XX, where “XX” is the 35mm-equivalent focal length of the lens. This is called the reciprocal rule.
For example, if you’re using a 100mm lens, you can safely use a shutter speed of 1/100 of a second. With a 50mm lens, you can go a little slower at 1/50 of a second and still get acceptably sharp images.
IS, whether it’s a feature of the lens or camera, enables you to use a slower shutter speed. Depending on how advanced it is and how steady your hands are, you’ll likely be able to go somewhere between two and four stops slower. (Some manufacturers, like Canon, claim certain camera and lens combos can have up to eight stops).
With a 100mm lens, this means a shutter speed of between 1/25 and 1/10 of a second. In low light, that’s enough to make a big difference.
IBIS vs. In-lens Stabilization
The big distinction between IBIS and in-lens stabilization is where the stabilization mechanism is placed. With IBIS, the camera sensor itself moves slightly to counter any camera shake. With in-lens stabilization, an additional lens element moves and ensures a stable image protection on the sensor.
Neither system is superior to the other—they both have their advantages.
IBIS works best at shorter focal lengths. On long focal-length lenses, like a 300mm telephoto, the sensor can’t move enough to overcome the highly magnified camera shake. However, since the stabilization is done in-camera, all lenses can be stabilized—even those that weren’t originally designed to be.
In-lens stabilization is less convenient and more expensive than IBIS. While longer lenses with IS have systems designed to accommodate a lot of shake, you’re paying a premium on every lens. It’s also another fragile thing that can break if you accidentally drop a lens.
How Much Does It Matter?
Historically, Canon and Nikon have relied on in-lens stabilization for their lenses. It’s only with the release of their latest mirrorless cameras that they’ve started using IBIS. This is largely because Sony has been making a big deal about the IBIS in its mirrorless camera range.
IBIS is certainly a nice feature to have, and it can enable you to take shots you’d otherwise miss. However, just like any kind of image stabilization, it comes with the following important caveats:
It only reduces blur from camera shake: If you use a slow shutter speed, like 1/10th of a second, you can expect to get motion blur from anything moving in the frame, even without any camera shake. It’s most useful on longer lenses, but works best at shorter focal lengths: This isn’t a magic solution for wildlife or sports photographers. You’ll get better results by increasing your ISO or aperture: In most situations, this approach is more reliable than image stabilization.
Also, it’s worth noting that many of Canon and Nikon’s new telephoto lenses still feature built-in IS, which works in concert with IBIS to stabilize images. This means you’re essentially paying twice for stabilization.
