The Binocular Site
The Lowdown on Zoom Binoculars
Imagine making your out-door stargazing experience like a trip to the planetarium, or reading players’ lips as you watch your favorite football game. Or spotting a bird in the distance then zooming in to examine the finest features of its feathers.
Zoom binoculars can do this for you. Look for binoculars that have two numbers before the “x”. For example, 12-36x70 marks a set with magnification that can zoom from 12x through to 36x, with 70mm objective lens.
Do consider however that zoom binoculars will require extra focusing as you zoom in or out. You can use these typically from lower magnifications such as 15x while birdwatching or hiking, or zoom them right in so you feel you can touch that star with a magnification of 120x.
Keep in mind however that extreme zooms will narrow your field of view (FOV) significantly, and therefore re-mounting may be necessary as you zoom in, or while watching heavenly bodies such as the moon which will appear to move during earth’s rotation.
Therefore it can be worthwhile to also consider mounting equipment, tripods, and built-in features that make mounting those binoculars easy.
All Binoculars, Great & Small
While many zooming binoculars fit easily in the palm of your hand, there are ultra large options available as well for more power. Bushnell offers a nice compact zoom option in their Powerview binoculars, which are 7-15x25. The magnification range is optimal for so many uses, and the objective lens diameter is decent too. Perhaps most importantly, they are sleek and streamlined, making them easy to use at the game or while on a road trip.
If you want even more power in a lightweight package, check out Nikon’s Action Zoom XL, offered in 10-22x50. While these are a little over 2lb, they do come with a tripod adapter and tripod for mounting them. You can easily put them on the tripod for extra stable viewing while zooming in and out, or just keep them in hand.
And if they don’t excite you, try Nikon’s 8-24x25 EagleView Zoom Binoculars. The much smaller objective lens size will still fit your bright light viewing but be much slimmer. They feature central focusing, diopter adjustment for comfortable viewing, and weigh in at only 12.3oz.
There are certainly large size zoom sets as well. Consider Barska’s beautiful Gladiators, which at 12-60x70 offer extreme magnification, extra giant lenses, and of course a built-in tripod adapter. These are high quality, yet not too expensive either.
There Are Some Caveats
That said, zooming binoculars are not for all. There are so many small, moving parts involved in zooming that the potential for damage and misalignment are higher. Since binoculars operate as two separate telescopes, the zooming mechanism must be installed into each side and kept in alignment using a linkage band. Naturally this small band makes it difficult to keep each side of the binocular in alignment, and is particularly prone to damage over time.
Zoom binoculars offer a small FOV at all magnifications too. By looking closely at the specifications you will find that these models tend to offer as little as half as much FOV as fixed magnification options. And while very high magnifications are often available, image quality can be very degraded at such magnifications or when binoculars are subject to the slightest wobbling involved in being held by hand.
Zooming features are relatively new and in many cases can still use improvement. The cost in weight and functionality caused by zoom can reduce the quality of other features, so shop carefully. Beware of inexpensive zoom binoculars as many models do not do the feature justice, and where a price seems too go to be true, it probably is.
If you’re unsure about investing in zoom binoculars, consider specialized eyepieces instead. There are different eyepieces available to show various levels of magnification even while using fixed magnification binoculars. Fixed magnification binoculars will be less expensive and more versatile, without the performance limitations of some zooming binocular models.
Binocular models with specialized eyepieces will be listed with a “/” symbol rather than a hyphen, as in “25/40x100”, which suggests eyepieces are included with magnifications of 25x up to 40x. You can also easily find eyepieces separately; just be sure they will work with your binoculars.