Different camera manufacturers have different names for this technology, so IS is also known as VR, MEGA O.I.S., SR, OS, SSS, VC. And although the technologies involved may differ from one manufacturer to another, the majority of the end users couldn’t care less, as long as they get what they paid for.

Two technologies can be used to achieve image stabilization:

• Lens Shift, in which the lens elements counteract camera shake by shifting. Other names for this technology, found especially in public forums, are in-lens stabilization, lens-based stabilization, and others.
  
• Sensor Shift, where, in response to camera movements, the camera’s sensor moves to prevent image blurring. This is also known as in-body stabilization, body-based, etc.
  

Be warned though; don’t be fooled by misleading advertisements and marketing campaigns. You may see from time to time other types of “image stabilization” in digicams, ones which involve high ISO settings, e.g. 800, 1600… Increasing the ISO setting means that the camera sensor amplifies the light coming from the lens, which in turn means that you can set faster shutter speeds than with low ISO numbers. But using a high ISO also means noisy photos (the higher the ISO setting, the more noise you get in the final picture). This is not image stabilization, like some manufacturers like to advertise it. Maybe in the near future, some really smart company will start to sell cameras with free tiny tripods included in the package, and they will call that “image stabilization”. After all, a tripod stabilizes the camera, right?

Before comparing lens-based and body-based stabilization technologies, we must note that using them does not prevent motion blur; it reduces the effects of camera shake. Motion blur is caused by the subject’s movement; camera shake is caused by the photographer’s unsteady hands. Some cameras offer the option of using stabilization in panning mode, when the photographer follows the moving subject. In this mode, stabilization counteracts vertical shake only.

If you are planning on buying a DSLR camera, first try to understand the difference between lens shift and sensor shift stabilization:

1. At shorter focal lengths, both systems do a good job.
   
2. At longer focal lengths (telephoto lenses), lens shift stabilization is better. This is because longer focal lengths (when you zoom in) exaggerate the effect of camera shake, and tiny movements of the camera translate into significant movements of the image on the camera’s sensor. Sensor shifting technology is (yet) incapable of correcting this, as it would mean a bulkier camera body and bigger components of the optical system of the body, to allow for larger shifts of the sensor to reduce blurriness. And this also would mean more expensive camera bodies.
3. Lens shift technology will cost you more, because you will have to pay for the IS technology every time you buy an IS-lens. So if you plan on purchasing more than one or two lenses for your camera, you have to think if the additional costs justify the benefits of having in-lens stabilization.
4. Sensor shift technology is cheaper. You pay for it once, then you can buy non-IS lenses for the body. You can even equip your camera with very old lenses, which were manufactured long before modern digital cameras were born. You can buy those in good condition and extremely cheap, too. Although it’s not guaranteed that image stabilization will work with every lens that fits into the camera body, there’s a good chance that it will.
   
5. If you know you will never purchase more than two lenses for your DSLR, then it’s a question of preference. Chances are, if you’re not a professional or a very serious amateur photographer, you won’t need many lenses.
6. In-lens stabilization allows you to see a stabilized image in the viewfinder. Sensor shift doesn’t. That’s because DSLR cameras have an OVF (Optical ViewFinder), and the image you view in the viewfinder comes directly from the lens, and not from the camera sensor.

Canon’s IS, Nikon’s VR (Vibration Reduction) and Sigma’s OS (Optical Stabilization) technologies, among others, are found only in the lenses. Tamron, who doesn’t manufacture camera bodies, sells several VC (Vibration Compensation) lenses. If you are considering purchasing a camera with in-body stabilization, such cameras are made by companies like Sony, Pentax, Olympus, and others.

Nothing beats good photography techniques, and learning how to hold the camera in your hands and how to stand while taking pictures is of utmost importance. Image stabilization is a very nice feature to have in a DSLR, be it in the body or in the lens. First decide on a budget, then on the focal lengths you will need in lenses, and it shouldn’t be too hard to decide which type of image stabilization suits you more. Although image stabilization doesn’t perform miracles, it will make you more confident when taking challenging pictures, and more happy when viewing them.