Image Stabilization is a feature that can potentially help create sharper images, by compensating for slight shakes or vibrations in the camera, usually when capturing photos hand-held. Image Stabilization (IS) is the official name of Canon's lens-based stabilization system, however other camera and lens manufacturers also have their own stabilization technology, such as Nikon's Vibration Reduction. (VR)
Technical Explanation of Image Stabilization
Image Stabilization technology is a broad group of optical, mechanical, and electronic methods for reducing image blur caused by camera shake. It is also the name of Canon's own exclusive technology, (IS) which is a lens-based optical stabilization found in some but not all of its EOS EF, EF-S, and EF-M lenses.
However practically every other camera and lens maker offers one form of stabilization or another. Here is a list of the more popular stabilization technologies:
IS - Image Stabilization (Canon)
VR - Vibration Reduction (Nikon)
VC - Vibration Compensation (Tamron)
OS - Optical Stabilizer (Sigma)
OSS - Optical Steady Shot (Sony)
SR - Shake Reduction (Pentax)
OIS - Optical Image Stabilization (Fuji, Olympus)
Dual / Mega / Power OIS - (Panasonic)
What Is IBIS?
IBIS stands for In-Body Image Stabilization. Originally it was a term dubbed by Olympus, however it has been more widely adopted as the style of stabilization that relies on sensor-based stabilization motors, electronics, and gyroscopes, as opposed to optical, in-lens stabilization.
Although IBIS is most widely available in various brands of mirrorless cameras, it is not a mirrorless-exclusive technology. Pentax DSLRs have used sensor-based mechanical IBIS for numerous camera generations.
In-body image stabilization can be highly effective, compensating for many "stops" of potential camera shake. In the newest technologies, in-body stabilization can be even more effective than optical-only stabilization, and in some cases, sensor-based stabilization can work in conjunction with lens-based stabilization. (Sony FE and E mirrorless cameras, plus the A99 mk2)
What Is Digital / Electronic Image Stabilization?
Some stabilization techniques do not use mechanical motion at all, but instead perform the stabilizing electronically by using gyroscope input to simply change how the image sensor itself is "read". The limitation to this technology is that, in order to be effective, the sensor needs to be physically larger than the normal image circle, (so it has "room" to move the image recording around) ...or the image itself is cropped, and has a lower resolution than an otherwise static, un-stabilized scene would generate.
What Is 5-Axis Image Stabilization?
5-Axis Image stabilization is a term often used by Sony as the name of it's latest, most comprehensive stabilization system, however the concept itself is not necessarily exclusive Sony technology. The 5 axes (axises?) are:
1, 2: X & Y (linear, up and down motion)
3: Roll (angular rotation, along the same 2-D X & Y axes)
4, 5: Pitch & Yaw (angular tilt & swing rotation, not on X/Y/Roll axes)