Image-stabilized binoculars are binoculars that have special technology incorporated in them to help keep the image seen through the eyepieces from shaking. They accomplish this task through tools such as electronic gyroscopes, electronic processors, and liquid-filled prisms. The binoculars have many of the same features that other more traditional models have, but may be slightly bulkier, especially around the eyepieces. The added bulk is to house all the additional technology that image-stabilized binoculars must have.
Electronic gyroscopes are one of the most common ways image-stabilized binoculars work to make sure images do not have much, if any, shake in them. The gyroscope is powered by a small internal motor, and can work even when the specialized binoculars are shaken strongly. The mechanism that causes the gyroscope to react can take some time to find its correct attitude. Therefore, the system may not be the best choice for those who are sporadically moving the binoculars; they are at their best when stabilizing the vibrations of riding in a moving vehicle, for example. Also, these usually require batteries, which can be problematic in cases of extended use in wilderness areas.
Manufacturers also use computer processors to help stabilize images in binoculars. These systems use sensors that are placed in various locations inside the image-stabilized binoculars, and transmit information to a central processor. That processor then works to control a prism, thus stopping the image from shaking. These tend to work much faster than electronic gyroscopes.
Another system manufacturers use is known as cardanic suspension. As the name suggests, this technique utilizes a liquid-filled prism that is suspended, which enables the prism to move on an X and Y axis. Therefore, the prism is able to move in any direction in which the binoculars may be turned. Furthermore, this type of system is very responsive and stable. Unlike electronic gyroscopes, these binoculars also do not need an outside power source in order to operate.
While all of these systems may have their advantages over traditional binoculars, they are also more expensive than the average pair of binoculars. Often, for the same magnification and quality, image-stabilized binoculars may be at least three times more expensive than a traditional pair. Depending on the technology and the brand, some may be even more expensive.
Another drawback to such binoculars has been the weight. With the additional components, the binoculars can be heavier than more traditional models, which can be a discomfort to a user who is holding them up for extended periods of time. Magnification strength and other materials used can also add to the overall weight of the models. As the technology advances however, the added weight has lower than it once was.