Selecting a Pair of 8×42 Binoculars
Outdoor enthusiasts often find that the ubiquitous 8×42 size binocular strikes an ideal balance of power, brightness and portability. If you need optics for birding, hiking, hunting, safaris, or casual stargazing – or if you’re not quite sure what you will use binoculars for, you just know you want some – then let this design be your starting point.
The title numbers denote the magnification (8x) and the aperture (42mm).
In the author’s experience, 42mm binoculars are approximately the maximum size binocular that can be comfortably carried on the person during physical activity such as hiking. They can be reasonably hung around the neck or fit into small stowage such as fanny packs and light runners’ backpacks.
The weight and size of 50mm glasses makes it difficult to perform physical activity while carrying them loosely around the neck, and they are typically too bulky to store without a proper backpack.
In addition, the lighter weight of 42mm binoculars allows one to store them in a more accessible part of one’s backpack, whereas a heavier 50mm instrument ought to be carried deeper inside one’s kit for a proper weight distribution.
The downside of 42mm binoculars is their reduced light-gathering power, only 71% as much as 50mm binoculars. However, they are still large enough to be useful at night.
In fact, for most terrestrial purposes, the extra glass in a 50mm binocular adds nothing to the brightness of the image. This is because the maximum effective aperture of a binocular is determined by two things: the diameter of your pupil, and the magnification of the binocular.
If the exit pupil (aperture divided by the magnification) exceeds the diameter of your pupil, then some of the light gets wasted – you won’t notice any improved brightness from the extra aperture. The exit pupil of an 8×42 binocular is 5.25mm.
An 8×50 binocular would have an exit pupil of 6.25mm. But if your pupil diameter is only 5mm, the extra light will get wasted.
And on average, our daytime pupils range from 5mm (for the very young) to less than 3mm (for the very old). Our pupils are larger at night, but once we hit the age of 50 our average nighttime pupil size falls to 5mm as well.
Increasing the binocular aperture can allow you to use greater magnification while keeping the same exit pupil and image brightness as a smaller, lower-power pair. However, there are downsides of magnification even when image brightness is not an issue.
One is image shake: steadier images are more pleasant and make it easier to pick out details. Higher magnification also restricts the field of view of a binocular, making it more difficult to view extended objects such as scenery, sports games and the Milky Way.
It is also easier to track birds in flight when you have a wide field of view. Thus, while 10x is typically considered the maximum useful magnification for handheld binoculars, a more conservative 8x is preferable for many people.
So the 8×42 is a good all-round design that compromises between these various considerations. A larger low-power binocular is going to waste light most of the time, meaning that the extra weight and cost is unnecessary; a larger high-power binocular is going to have narrower, shakier images.
Meanwhile, a smaller binocular that aims to provide the same level of detail will have to sacrifice image brightness to a degree that would be noticeable for younger daytime users as well as any nighttime user. This gives the 8×42 the title for being the default general purpose binocular for terrestrial purposes. (For astronomy, 50mm binoculars are recommended, though 8×42 ones can be used as well with nice results.)
As a result, the 8×42 market is flooded with offerings from a wide variety of optics brands. While this means that virtually everyone can find a pair that is suited for them, it also makes it a daunting task for a first-time binocular buyer to try to sift through the variety of models and locate the right choice.
Fortunately, in this article we have compiled a list of excellent 8×42 binoculars across the price range from bargain to premium.
If you’ve decided upon your budget, then finding the appropriate binocular will be straightforward. If you’re not sure how much you ought to spend on a binocular, then these reviews should give you an idea of exactly what you can expect in exchange for spending more money on a more expensive pair.
1. Nikon Aculon A211
The Aculon 8×42 is unique as an entry-level 8×42 binocular because of its porro prism design. Most 8×42 binoculars use roof prisms, which can be identified by the smooth straight shape of each ocular assembly.
But this Aculon has the big, angled classic binocular look of the porro prism design. While this makes it bulkier than others, it also provides brighter, clearer images at a lower price point.
The roof prism design is difficult and costly to produce well, so porro prism binoculars come recommended in this entry level price range as long as you can handle the extra size. You would have to shell out much more money in order to get roof prism binoculars with better optical quality than this.
The images are great, and the construction is solid (though neither waterproof nor fogproof). User impressions are consistently excellent across multiple vendor websites as well as binocular forums.
With the minimal 12mm eye relief, eyeglass wearers will have to take their glasses off in order to use the Aculon.
If you have nearsightedness or farsightedness, the focuser should be able to accommodate your vision, but astigmatism will not be corrected. This is true of any binocular with short eye relief.
2. Vortex Crossfire
The tethered objective lens caps are a great feature for convenience in the field, and the ocular lens cap has attachment points to be tethered as well with a strap.
The prisms are good-sized with no indication of vignetting, at least one internal baffle can be seen, and the full multicoatings appear reasonably effective with consistent mild green reflections.
I did not notice any flaws in the internal construction. The focus wheel is usable even with thick pigskin winter gloves, though not ideal. The twist-up eyecups function smoothly.
The body is armoured with a hard thin layer of rubber, and the binoculars have a clean, simple overall appearance. The nylon carry case is nice with loops for attachment to your clothes or gear.
The Crossfires deliver pleasing sharp images. Even on the 10×42 model with its higher magnification, there is no noticeable chromatic aberration if you aren’t looking at a bright target.
Edge-of-field distortion, so often the Achilles’ Heel of low and middle priced binoculars, is relatively minor. There is a small amount of glare when looking at the Moon, but it is not objectionable.
The fogproof construction held up in practice – moving from freezing outside temperatures into a heated apartment caused all four exterior lenses to immediately fog over, but the inside remained clean. Reviews from other users are generally positive as well – more so than for competing models such as the Celestron Nature DX and Nikon ProStaff 3S.
3. Nikon Prostaff 7S
This technology reduces the image degradation caused by prism reflections, and allows roof prism binoculars to finally reach the high optical standard set by cheaper porro prism designs while taking up less size and weight.
Nikon’s Prostaff 7S is the best-regarded option in the entry level of this price range. The optical quality is outstanding with sharp, bright images that will satisfy most users for all practical intents and purposes.
Its long eye relief makes it well-suited for eyeglass wearers. Its field of view is a modest 6.8 degrees.
The Prostaff 7S’s black armoured body with attractive gold lettering is a refreshing throwback compared to the generic greens, blues and browns of so many other modern binoculars.
4. Celestron Granite ED
They feature extra-low dispersion glass, which suppresses the chromatic aberration inherent to glass optics. Not only does this suppress the distracting coloured fringes that show up around bright objects in other binoculars, it subtly improves contrast across the field of view.
The resulting image quality is top-notch. There is some degrading towards the edge, but that is acceptable for binoculars with such a wide field of view – over eight degrees!
The 17mm eye relief is long enough for eyeglass wearers, and the two-metre close focus distance allows for some butterfly watching.
The mechanical construction of the Granites is also excellent. All of their functions such as focusing operate smoothly. Like many other premium binoculars, they are made from “magnesium” (probably magnesium-aluminum alloy in reality), though this is not necessarily better.
Probably the best-known competitor to the Granite is the Nikon Monarch 5, also available in 8×42. Both are widely regarded as superb binoculars, but the Granite gets our pick because of its much wider field of view, despite the resulting edge distortion.
Purists may prefer the Monarch 5 or other narrower field binoculars.
5. Zeiss Terra ED
Zeiss’s Terra line with ED glass puts outstanding German optical and mechanical quality into a – relatively speaking! – affordable package. Zeiss has managed to accomplish this by manufacturing them in China, just like most other binoculars on the market.
While purists for top optics may not be impressed, Chinese binocular manufacturing has greatly improved over the last decade or two. The design and quality control standards of a brand like Zeiss go a long way towards ensuring that Chinese optics meet premium standards.
So the Terras are nothing to sneeze at – at this price point, just about every feature that you’ve been taught to look for in a binocular comes standard.
The difference between the Terra and competitors such as the Granite and Monarch is a more subtle matter of engineering practices and design choices which are individually minor but collectively add up to leave mere mortal binoculars falling behind in optical performance and mechanical quality.
The Terra has tack-sharp images across most of its wide seven-degree field of view. Users rave about the wonderfully clear views. Unlike lesser binoculars, you don’t have to focus your target in the centre of the view in order to get an excellent view. It also focuses all the way down to 1.6 metres, facilitating pursuits like butterfly watching.
The Terra is made from lightweight reinforced polymer. The included accessories are all well made. Finally, getting your choice of three colours – black, gray or green – is a nice touch.
Beyond this point, there are steeply diminishing returns to pricier binoculars. Many users won’t notice any significant difference between an excellent binocular like the Terra and the most elite brands costing 2-3x as much.