Zoom Binoculars - Ready to Take the Bad with the Good?

October 8, 2009 by binocular

Zoom binoculars may not be for everyone, but they certainly fill a widespread need in the binoculars marketplace. Don’t just assume that they’re better than the non-zoom variety. You’ll want to carefully consider what you need in a pair of binoculars and match up the various features offered by available models to pick the best ones for your situation.

First, what are zoom binoculars? They are simply a pair of binoculars that allow a variable amount of magnification or power within a set range. So where a set of fixed binoculars might have a set power of 8, zoom binoculars can offer a range of powers from 7 to 15 or 10 to 20. The magnification is typically controlled by a lever that moves the lenses back and forth.

This brings us to the first problem with zoom binoculars, almost all of which stem from the movement aspect. Mechanical systems are never perfect, and since there are two lenses in a set of binoculars that means that as the zoom mechanism is operated, each side will move different amounts. Don’t get me wrong, I’m not talking an inch or anything, but when you are talking about optical systems (and highly magnified ones at that) even tiny amounts of discrepancy can become an issue.

Another problem is related to the alignment within the lens. Once again, the amount that an individual lens needs to shift, misalign, distort, or in any way disagree with the other in order to degrade your viewing enjoyment is miniscule. As soon as you introduce moving parts, a level of precision sufficient to overcome those imperfections is essentially unattainable. As you operate the zoom lever, your image quality will suffer due to minute shifts.

The last limitation imposed by zoom binoculars is that they will have an impaired field of view, even when fully zoomed out. A fixed pair of binoculars at the same magnification would have a larger field of view, offering better visibility. This will have a net effect of allowing you to see less of whatever you are observing at a given zoom level.

The bottom line is that if your application requires you to zoom in and out, then you have little choice but to opt for zoom binoculars. Otherwise, you will be able to purchase binoculars for the same price that will offer superior image quality and integrity. If that’s more important than being able to get a little closer view on demand, fixed binoculars are your best bet.