Engadget reported earlier this week that Canon had an “eye-based biometric photo watermarking system” patent pending. That is, the camera will have a sensor which will read the user’s iris and will record a registration code embedded in the image at the moment of power-off. » MORE

When you take a picture with a long lens, it’s tough to keep the camera steady. Long focal lengths accentuate and emphasis any tiny little movement in the camera itself. That’s where stabilization comes into play. However, there seems to be some confusion out there about image stabilization technology, not least of which is how it works, but also how optical stabilization compares to internal stabilization like on some SLR’s and on many point and shoots.

Nikon calls their SLR stabilization VR (Vibration Reduction) and Canon calls it IS (Image Stabilization). It usually appears in longer lenses (those that have a focal length longer than 100mm or can zoom out past that length), but the two systems work similarly. VR/IS is a mechanism that is built into the lens, which detect angular velocity and compensate for it by moving around the lens elements. This is explained in greater detail at Nikon’s website, but the basic idea is that it all happens in-lens with sensors and control mechanisms.

This is optical stabilization. It’s happening within the optics of the lens.

The other kind is often called mechanical or digital stabilization, and that happens in the camera body itself (no matter what lens you have) by moving the sensor around. Sony calls it Shake Reduction (SR). Though the results are the same, the disadvantage is that in an SLR you’re viewing the image through-the-lens (TTL) and since the lens isn’t the stabilizer, the image won’t appear stabilized to your eye.

The other question that is asked often is whether or not to use stabilization when attached to a tripod, as some manufacturers recommend against it. With almost all these camera stabilization systems, when you lock down the camera, the stabilizer could be causing more motion then it’s reducing – since there should be very little motion on a mounted camera body anyhow. VR, IS, SR, or whatever you use – is best reserved for handheld shots where there is more motion introduced to the gear.