Zoom binoculars are one of the rarest types of binoculars on the market. They are versatile and very affordable, providing an optical compromise with multiple magnification levels in just one pair. Magnification therefore isn’t fixed and can be adjusted with zoom-in and zoom-out system. When tracking the following object, you can easily change from low to high power in the matter of seconds, to get finer details and improve your visual experience. Zoom binoculars are mostly suitable for long range observations such as marine applications and astronomy. They also come in handy when hunting, but are providing smaller field of view and are therefore less suited for bird watching and other dynamic applications. The quality of zoom binoculars is not as good as in high-ends. The mechanism of zoom binoculars is a little bit complicated and is equipped with flexible linkage band that helps to maintain clear images of moving lenses when adjusting the focus whilst zooming. The perfect synchronization is thus harder to maintain due to many zoom mechanism parts, making images fuzzier than by the conventional ones with fixed magnification. Due to this moving mechanism, lenses are hard to perfectly align, also providing collimation issues.
Beginners in astronomy sometimes have the desire to purchase zoom binoculars, because they allow them to look at a wider area, and focus on a certain part of the sky, where they find the detail they want to look closer at. In theory, it sounds good, but in practice, these zoom binoculars have so many compromises on optical performance that the actual image quality is very poor.
Many zoom binoculars manufacturers produce them with very compact lenses, 24 or 30mm, mainly because they are usually bought by travelers, scouts, mountaineers, etc... They are expecting and thinking that with zoom binoculars it will be easier and better to observe nature. The truth is that they are usually not such a good choice.
When buying high-quality zoom binoculars, there is a possibility that you can watch fast-moving birds at a lower magnification and follow them in motion. Lower magnification is also suitable for slower, bigger birds and those in nests. When you want to see more details, and, for example, define their gender and age, then you put it on a higher magnification, so you get a better resolution to see the details better.
Many manufacturers often exaggerate with magnification- it is almost impossible to observe with more than 12x magnification and hold the binoculars in hands, because of the shaking. We recommend those with a variable zoom in the lower area (up to 12x).
Leica is the only premium manufacturer that produces High Quality zoom binoculars and also the only one among those, that dared to tackle this task and produce such binoculars, which still have good optical properties. However, the magnification is not continuous; whether it is 8x or 12x. Between this two magnification, the image is blurry. It is the only choice for those who wish to buy zoom binoculars with high image quality.