Image Stabilization: When to Use it and When to Turn it Off
Image stabilization, or “vibration reduction,” “O.I.S.,” Optical SteadyShot, SR, VC, VR, MegaOIS, and other equally catchy monikers, are technologies that enable photographers to take pictures under lighting conditions that once upon a time would have been considered too iffy for capturing sharp still images. Depending on the make, model, and vintage of your IS-enabled camera or lens, image stabilization allows you to capture sharp pictures at shutter speeds three, four or five times slower than normally possible.
Note: The rule of thumb for capturing sharp, handheld imagery is that you shouldn’t handhold a camera at shutter speeds slower than a shutter speed equivalent to the focal length of the lens. This means a 500mm lens shouldn’t be handheld at speeds slower than 1/500-second, a 300mm lens slower than 1/300-second, a 50mm lens slower than 1/50-second, and a 20mm lens slower than 1/20-second.
Add image stabilization into the mix and suddenly you can now capture sharp images of still objects with a 500mm lens at speeds down to 1/30- to 1/15-second, a 300mm lens at speeds down to 1/15- to1/8-second, and a 20mm lens at speeds down to 1 to 2 seconds.
The problem is that while setting a new camera up for the first time, many shooters turn the camera or lens’s image stabilization on and never look back, figuring “If I need it, it’s on,” but depending on the make, model or vintage of your particular camera or lens, that may or may not be such a good idea.
Before getting into the nitty-gritty of the subject, it’s important to clarify a common misconception about image stabilization, which is that it enables you to “freeze” fast-moving objects at slower shutter speeds. This is totally false. Image stabilization only allows you the ability to capture sharp images of static subjects at slower speeds. Moving objects will be equally blurry or streaky—and in some cases blurrier or shakier with the IS turned on.
There are two types of image stabilization (IS): lens based and in camera. Lens-based image stabilization is a process in which gyroscopically controlled electromagnets shift a floating lens element orthogonally to the optical axis along the horizontal and vertical plane of the image in the opposite direction of the camera movement, which effectively neutralizes any signs of camera shake. Depending on the make and model of the camera or lens, measurements are taken about 4,000 times per minute for seamless on-the-fly stabilization corrections.
In-camera IS works in a similar manner, but instead of a lens element, the camera’s imaging sensor is shuttled about in the opposite direction of the camera’s movements in order to similarly dampen the effects of camera shake. As for which form of image stabilization is better, there are pros and cons for both sides.
The advantages of in-lens image stabilization include smoother performance when using longer focal length lenses and the ability to see the effectiveness through the camera’s viewfinder. The downside of lens-based image stabilization is that it’s not available as an option for all lenses and it adds to the cost of the lens. But then again, if you don’t need IS you often have the option of purchasing a non-IS version of the lens, or at least something similar.
The pros of in-camera image stabilization are that you gain the advantages of IS technology with any lens you can mount on the camera for considerably less cost than multiple IS-enabled optics. The downside of in-camera image stabilization is that it’s less effective at smoothing the bumps when shooting with longer focal length optics when compared to lens-based image stabilization.
The most basic form of image stabilization is Dual-axis image stabilization, which is designed strictly for handheld imaging and should be turned off when you mount your camera on a tripod. If you mount the camera on a tripod (or similar stable platform) without cutting the IS, you risk creating what’s called a feedback loop, in which the camera’s IS system essentially detects its own vibrations, which are picked up and amplified by the tripod, which in turn forces the camera’s IS system to work increasingly harder to quell the elevating levels of camera shake. Worst case scenario: things spin out of control and your camera ends up in the repair shop.
Many newer IS systems can detect when the camera is secured to a tripod, or have a “Tripod” mode that automatically compensates for the added resistance of the tripod, or shuts the IS function off entirely. If you already own an IS-enabled lens or camera or plan on purchasing one, make sure you read the fine print in the product manual to verify the type of IS system with which the camera or lens is equipped.
An additional downside of many simpler dual-axis IS systems is that they hamper smooth side-to-side panning action. By design, dual-axis IS systems interpret and react to pan movements as shake movements, which results in jerky, uneven sideways pan motions when shooting stills and video. To remedy this issue, lens manufacturers have updated many of the newer IS-enabled optics with a Pan Mode, which allows for smoother, jerk-free panning motions.
Note: Camera and lens manufacturers use differing nomenclature to describe similar forms of functionality. Make sure you read the fine print when researching the features of camera/lens IS systems.
If you shoot with a camera that features in-camera IS (i.e. Sony Alpha/Minolta, Pentax, Olympus) and plan on using a third-party lens that also features an IS system, turn off the camera’s IS system and rely on the lens’s IS system to smooth out the bumps in the road. Running both systems simultaneously will most certainly compromise your ability to hold things steady, not to mention cause damage to one or both of the IS systems.
On a final note, it is well worth mentioning that for the sharpest results when photographing still subjects, nothing beats a camera mounted on a sturdy tripod with the image stabilization turned off. This is because image stabilization, by its very nature of using motion along one axis to counter motion in the opposite axis, often creates varying degrees of image degradation of its own, whereas a camera firmly coupled to a stable tripod and tripped with a cable or remote release with the mirror locked in the up position will in almost every instance take a sharper picture.