For the money and quality, most non-profits or struggling graduate students with an observational element to their project go with Eagle Optics, the company I feel has set the bar. The other common player we see at this table is Nikon, specifically their "Monarch" model.

Most binoculars offer somewhere between 8 and 12 times magnification, as this is generally the ideal range for bird watching and general wildlife viewing. Beginners should probably veer towards the lower end of this range. While greater magnification makes for a more close-up view, it also presents a few issues. The first is hand shake. At larger magnifications, any twitch of the hand becomes much more noticeable and can make the image appear blurry as a result. As you use binoculars more and more, you'll likely adapt and figure out how to reduce hand shake, but you'll probably want to start out with a more forgiving magnification.

The next major advancement was Keplerian Optics which used a convex eyepiece and relay lens in between the objective lens and eyepiece to flip the image. The lengths of these binoculars and telescopes were quite large to account for the long focal length. The larger the objective lens, the more light that can get into the binoculars, and thus the brighter the image. Larger objective lenses also make the binoculars themselves larger and heavier. You'll want to find a balance between brightness and portability that works for you. The condition of seeing two images because of misalignment of prisms is called de-collimation. It happens mostly due to an internal fault in binos. We cannot prevent the misalignment, the only thing we can do is fix it. Pinpoint the fault in prisms by aiming at your target (a wire, or a straight line). If the fault is present, you will see the target line on different heights through both sides.

This guide was to acquaint you with how to repair binoculars at home. And I am pretty much sure I have been successful in doing so.

Uses

The multi-layer anti-reflective lens coating reduces glare and chromatic aberration, a problem that many other Vivitar binoculars seem to be dealing with. As a result, the images you’ll see are clearer.