What are zoom binoculars?
Binoculars that have continuously variable magnification are called zoom binoculars. Zoom binoculars are designated by their magnification range, such as 10-30×60 or 12-36×70. The hyphen indicates that the magnification is variable from the first number to the second. This is done by moving a zoom lever to increase (“zoom in”) or decrease (“zoom out”) magnification. Conversely, a binocular with a single magnification is called a “fixed-power” binocular, and is designated with just one magnification number, such as 10×50 and 20×80. Note that some binoculars have multiple magnifications, but are not zoom binoculars. These are designated with a slash, such as 25/40×100. The various magnifications (in this case, 25x and 40x) are obtained by switching in different pairs of eyepieces. Zoom synchronization Many of us have high-quality zoom lenses for our cameras, and they work quite well. Why not take advantage of the same technology with our binoculars? The primary problem with using zoom le
