What these coatings do is to assist light transmission. It is important to note how the manufacturer describes their coatings as they are not all created equal. Ideally you want to see "Fully Multi-Coated" which means that all air to glass surfaces have received multiple layers of antireflection coatings. If you just see "Fully Coated" or "Multi-Coated" it means only some surfaces have coatings or they only have a single coating and thus will not perform anywhere near as well as Fully Multi-Coated binoculars assuming everything else is equal.
Field of View is expressed as feet at a thousand yards. This is fine if you are in the artillery, but astronomers use degrees to define the field of view. If you see on your binoculars a field of view 316 feet at a thousand yards, it means the field of view is 316 feet from edge to edge in your binoculars. To convert this to astronomical field of view or degrees divide by 53. In this case 316 divided by 53 equals 5.96 or 6.0 degrees field of view.
Recommendation: while few people will buy binoculars solely on the strength of a warranty, and hopefully you won’t need to avail of it, a manufacturer’s willingness to stand over their product is obviously a major plus. Focus on features and the overall quality of the binocular first — but do consider the warranty in the “mix” before making your final selection.
Another advantage of the larger objective diameter is a larger exit pupil at the rear element of the binoculars, where your eyes are focused. With two binoculars of the same magnification, the circle of light hitting your eye is larger, with a larger objective. Therefore, an 8x42 binocular will have a larger exit pupil than an 8x35 binocular. A larger exit pupil generally means a more comfortable viewing experience.
If you can afford them, as they do cost a pretty penny, they will give you clarity unmatched by anything else. When you’re looking at something, you’ll feel like you’re actually looking through your own eyes, and not through a pair of rangefinder binoculars. This is the best of the best, the crème de la crème, if you will. The premium optics have a multi-layer glass, and fluoride, which results in a lot of light being able to go inside the lens. You’ll be able to see objects right before it gets completely dark, with ease. That coating we mentioned is LotuTec, and it also plays a big role in the vividness of the image.
The Carson RD 8 x 26 waterproof, Levenhuk Karma Pro 8 x 25, Maven C.2 10 x 28, and Minox 8 x 25 are part of a slew of “new compact” binoculars that resemble shrunken-down versions of the full-size 8 x 42 models, but were about two-thirds the size and weight. At this size, though, they’re too large to slip into most pockets, unless you have a huge coat on, taking away the very portability that we were looking for. I also found the quality lacking across the board—eyepieces that wouldn’t stop spinning (Maven), eyecups that didn’t sit flush with the eye (Levenhuk, Minox), and distortion of distant objects (Carson).
As a more general comment on the current state of binocular manufacturing: With things changing so rapidly, consumers should check that the pair they end up with is the same high-quality model we’ve tested. So many new binocular brands and models are in the market now, and some confusion is inevitable. Athlon Optics, a relatively new company, currently has 28 different models and six distinct binocular lines. If you’re the kind of person who prefers the stability (and availability) of a better-known brand, look toward our runner-up and budget picks.
Very bright, clear display with 4-step intensity adjustment; easily readable under any lighting conditions and against various subjects, with single or continuous measurement up to 8 seconds. Displays in increments of 0.1m/yd, when shorter than 100m/yds and in 1m/yd at 100m/yds and over. Auto power shut-off function saves battery life by shutting down after 8 seconds of non-use.
***Important Note: Most companies don’t reveal much detail when it comes to the below information. These are kept a secret so as not to lose a competitive advantage. For example, Zeiss has been in business a LONG time. They have perfected their engineering and coatings over many years and are not very willing to share their best practices with other companies!***
The Athlon Talos 8 x 32, Minox BV 8 x 33, and Vortex Diamondback Classic 8 x 32 are “tweener” or “large compact” binoculars—not particularly compact, but a size down from full-size. They feature the largest focusing wheel, wide/heavy bodies, and weigh as much as some full-size models. Though I wouldn’t trade them in for my go-to 8 x 42 pair (due to the narrower field of view), I actually found them to be a comfortable size for birding/nature-study, and didn’t find serious drawbacks during testing (though the Vortex Diamondback gave me minor eyestrain).
The Leupold Shadow Gray 6x30 BX-1 Yosemite Binocular features a compact form-factor outfitted with traditional BAK4 Porro prisms and a fully multi-coated optical path to display more depth of field than similar roof prism designs. The resulting images transmitted by the Yosemite binocular have lifelike depth and are crisp and clear with high-contrast and accurate colors across the field of view.
There is not much of a need for an astronomy binocular to be waterproof, water resistant is enough as using them at night can expose a binocular to dew and moisture, which can cause a non-waterproof model to mist up inside the mechanism. I would just like to say though that in general, better quality binoculars tend to be sealed and fully waterproof as well as fogproof and so this is one indicator to look out for if you want to make sure that the binoculars you are getting are of a good quality. (importance 2/10)
Zeiss brought a 20X binocular to market in 1990 which utilized an entirely mechanical "dampened stabilization mechanism." That is to say it has no electronic component to the stabilization and thus no batteries to replace. This approach, while doing wonderfully in its own right, doesn't seem to stabilize as thoroughly as the Techno Stabi, but is still quite good when considering that it has more dampening to accomplish at 20X than lower magnification powers. Some reviewers say that they consider the vibration in the stabilized Zeiss 20X60s is about what you'd expect from a 4X binocular or about half what you'd experience with a non-stabilized 7X50. Did we mention that there are no batteries to die just as you see a particularly astounding view?
Want really steady views? Invest in a dedicated binocular mount. This can be a simple "L" bracket ($10 to $20) that attaches to a tripod — or, much better, a fancy parallelogram-style mount ($200 or more) that holds your binoculars for astronomy pointing at any angle overhead while you raise or lower them to suit your eyes. This is especially useful for sharing views with others.
Really, you'll be OK with even smaller binoculars, as long as they are of high-quality optical glass. You can carry an 8x35 pair all day for bird- (or people) watching, and they won't make your arms tremble — and your stars dance like drunkards — when you pick them up at night. The wider view-field of most lower-power binoculars is usually a plus for skywatching.