Many people say that buying image stabilizing (IS) binoculars ranks among the top 3 most important things they have ever bought for their boats. You will see buoys, radar contacts, and navigational hazards much farther away than with non-stabilized models.
How much stabilization is needed? When binocular power increases above 8, hand tremor and platform motion begins to blur the image so that increasing magnification gives no better results. IS systems allow power to be increased without blurring. IS systems are described by the number of degrees of oscillation over which they have authority. Models with ±1° of stabilization are adequate for controlling hand tremors, but not the platform motion associated with being underway in a boat, airplane or car. For these, models with up to ±5°of stabilization is desired.
How is stabilization achieved? Models with up to ±5° of stabilization do this through a battery powered system of gimbaled digital servos, and piezo-vibration sensors. This system does away with the power hungry high speed gyros in older models and allows a lighter weight.