Zoom binoculars are binoculars equipped with modern imaging technology that allows variable closeups on viewing targets. Binoculars are handheld optical devices designed for use by both eyes, and are sometimes known as field glasses or opera glasses. They link two small telescope tubes through a single focusing device, using lenses and prisms. Now commonly equipped with innovations in optical and camera technology, binoculars extend their functionality with digital and optical zoom capabilities, as well as the ability to record images or video digitally. As with a camera, focal range may be enlarged digitally resulting in increased magnification and pixellated resolution loss.
With ranges extending up to 24x magnifications, zoom binoculars permit viewing objects with more control over focal length and distance. This is achieved by toggling a switch by the eyepiece. Additionally, these binoculars often come equipped with auto focus functions to make zooming much easier. Electronic image stabilization minimizes motion blur by adjusting prisms or the digital framing of the image, to make viewing in motion much easier. With new functionalities added, zoom binoculars tend to be priced higher than traditional mechanical models.
Other features of zoom binoculars may include multicoated optics, comfort-fitted eyepieces, and rubberized body armor for ergonomic comfort. Camera functions may consist of single image, continuous capture or video, and delayed shutter releases. Additional product features may include internal memory, cables, accessories, and software drivers. Broadband optics increase the transmission of light through the visible spectrum in order to provide clearer, brighter resolution.
The calibration of zoom binoculars is critical to performance, as each tube possesses its own lens system. Magnification draws attention to any discrepancies in the optics as well as motion blurs. Optical zooms preserve the resolution of the visible spectrum, but they rely upon the movement of lenses in which minute imperfections could distort imaging or focus. Digital zooms reduce mechanical inconsistencies at the cost of resolution, as these images are expanded the way one might stretch a digital photograph in photo editing software. Moving from smaller to larger resolutions results in information gaps that create the stairstep pixellated effect of an overenlarged digital image.
The ability of zoom binoculars to move with the viewing subject permits users a number of added advantages. Observations can be conducted from a distance with fewer observer effects, such as startling animals or distracting viewing subjects. Zoom functions limit field of view, compared with fixed binoculars at the same magnification. Fixed binoculars, by comparison, offer less flexibility for distance from objects. For people accustomed to the cross-functionality of digital imaging, including photograph manipulation and upload to web media, zoom binoculars provide added versatility in the digital age.