Three Points of the Compass recently made a plea for those venturing into the outdoors to consider carrying and using a lightweight monocular. But which to choose? Just a few minutes browsing Amazon, eBay, AliExpress and the rest of them immediately reveals how much dross there is to choose from. Take your time, read up on the subject and specifications and choose wisely.
Viewing anything with one eye rather than two has an effect. Hue and contrast are affected with the switch from one eye to two however the brain is a remarkable instrument and compensates effectively, it is the field of view and ease of handling that is the most crucial dividing line between binocular and monocular. I am always going to enjoy my experience and viewing quality more through a binocular rather than monocular however this is the compromise we all have to deal with when looking at inclusions and exclusions from our gear list. A monocular is less comfortable to use than binoculars but for the length of time most of us will use them on trail, this becomes less of an issue. If you have any interest in the landscape and nature through which you pass on a hike, a monocular might add to that pleasure. Sadly, it is a more expensive, better quality optic that will add to, rather than detract from, that pleasure. Poor optics are not enjoyable to use, choose wisely.
There are some really tiny monoculars on sale- 3x or 4x magnification. Many of these will come within a 50g weight limit but there simply isn’t any point in carrying such an item. In actual use in an outdoors environment, such a low magnification will not enhance a view of anything of interest to any appreciable degree. You simply wouldn’t use it. So moving up in magnification- for a number of years there was an extremely lightweight monocular that many hikers favoured, they may still do for all I know. Weighing around the 50g mark, the Brunton Echo monocular has probably been the lightest practical monocular option out there for those really looking to shave the grams while not spending too much. This little ‘scope was even offered as a ‘give-away’ by one trail magazine a few years back
The competitively priced and still obtainable 46g Silva Pocket Scope looks like it may satisfy the merely curious. This may even be a clone of the Brunton offering. Obviously at this price point, this monocular lacks Nitrogen fill or coated lenses, it isn’t weatherproofed at all, being barely splash-proof. Here is the rub. It is important to note that neither of these products is offering even reasonably quality glass or performance. All they can provide is a reasonably priced idea of potential, but not the actuality. Recent reviews have been recording the cheap plastic body breaking down and internal optics coming adrift. This is the problem. Cheap optics are cheap optics. They will not deliver performance, they will not last for more than a few years, if that. They will disappoint. Warranty will be poor or non-existent.
It depends whether you wish to ‘make do’, or choose quickly and buy twice, or take your time and take a further step up in quality (and price), while reducing the weight of the instrument and hopefully improving on the optical glass incorporated. It is not so much on a dry bright day where quality shines, it is the murky, damp, low light conditions where the extra money spent will reveal itself..
A step up in quality could be to something like the reasonably priced Hawke brand, where there is a range of different specification optics on offer, such as the Hawke Endurance ED 8×25 Monocular. All Hawke optics come with a lifetime guarantee. There are other brands offering similar but look for reputable names.
Which to choose?
I can only touch on the subject here as there is a lot to consider. If you are interested in selecting, trying and possibly buying a monocular for use on trail, then a bit of research is required in advance. Product specifications will vary from manufacturer to manufacturer but as a minimum, the points below should be considered. All the necessary specifications for any monocular worth buying should be easily found online. If they are not, then the manufacturer or seller is hiding something.
Any lightweight backpacker is always keeping an eye on how grams are creeping their way into the pack. Most will have not read this far as the idea of packing along a monocular is pure anathema to them. Especially now that I have disparaged anything around the 50g mark. But some people might countenance a weight penalty above that, so what might be acceptable? As always, it is a compromise. For better quality optics married with small size, weight will usually be above 100g with very few options below that and the cost considerably higher than the Brunton and Silva mentioned above. Many ‘monoculars’ are more toys, gadgets or spotting scopes than pocket monocular. Some good monoculars can be really hefty, especially if equipped with tripod mounts, separate focus rings or thick rubber protective armouring. But is something over 200g, 250g, 300g, or even more, really acceptable when it is very likely to see very little use and is fighting for space and justification in a lightweight setup? For most people, I suggest not. In practical terms, specifically with lightweight backpacking in mind, it is probably sensible to confine a search to pocket monoculars between 100g and 200g. While that considerably limits the choice, I will be looking at one remarkably lightweight offering from Opticron below 100g in a forthcoming review.
A wider Field of View can dramatically increase both size and weight of a monocular and such monoculars can start weighing between 350g – 500g. But if you feel the improved image quality more to your liking, then that has to be an added weight penalty you are content to bear.
Optical glass and Nitrogen fill
High quality optical glass will permit a brighter, clearer, sharper image with less likelihood of colour fringing or other aberration. Different optics manufacturers have different ways of describing any improved glass in their products. For example, both Hawke and Viking specify the inclusion of ED lenses in some of their products. ED glass standing for Extra Low Dispersion Glass. This reduces chromatic aberration, i.e. prevents the different colours that white light is formed of from breaking apart internally within the optic and causing a secondary spectrum of colour fringing. Image brightness in some of the better monoculars is also improved by the inclusion of specially coated lenses.
Study the specs sheet, look to see what optical glass is used and compare it to what other manufacturers are using. Look for the highest quality optical glass available within your price range. If a manufacturer isn’t specifying glass then you can take it that it is standard glass being used and steer clear.
Nitrogen fill denotes waterproofness and anti-fogging capability. Argon fill has started to become more commonplace for the same reason. Either are a ‘good thing’ and indicate that damp has been purged from the internals of the optics during manufacture. Either of these gas fills should be a minimum requirement. That said, the design of my long-term favourite monocular is such that it precludes a Nitrogen fill. Such is compromise.
Some might think that maximum possible magnification is a ‘good thing’. It isn’t. The more powerful an image the less field of view is presented, which can make finding, tracking and staying on an object of interest difficult. More important is that shake can become an issue as higher magnifications will also magnify hand tremors. More powerful magnifications really require a tripod to get the best out of them and it can be tiring and difficult to hold a more powerful magnification monocular by hand. I suggest stay clear of 10x if possible and only consider something like 7x or 8x as a maximum. Be careful though, the Nikon 7×15 High Grade (HG) Monocular might appeal at first glance, but despite its incredible lightweight 75g and meeting my suggested minimum acceptable magnification, some of its specifications are simply not good enough, not least the average Field of View and poor Exit Pupil (see below). Finally, steer clear of any zoom monocular, their performance is invariably really poor, especially in low light conditions.
The ability to close focus may be important to you if you are interested in flora, butterflies, dragonflies and the like. Usually lower magnification optics will permit a better close focus than more powerful magnifications. But not always, the Hawke monocular mentioned earlier will only focus down to five metres, which is woeful for that type of activity. If close-focus viewing is of interest to you, look for better than three metres close focus, preferably nearer two.
Field of View
Field of View is exactly how it sounds. It is the ‘width’ that can be seen when looking through a monocular. A wider field of view will aid in more easily finding and staying on an object of interest. It should be indicated on the data specification in metres (metric) or feet and yards (imperial), alternatively, it may be shown as Angle of View. In both cases, more is good. Either may be shown on the monocular itself. By way of example, the Viking 8×25 ED monocular has an Angle of View of 6.8° and Field of View of 119, meaning that a width of 119 metres is visible at a distance of 1000 metres.
Exit pupil is something to be considered. This is the virtual aperture visible through the monocular. The greater the exit pupil, the more light that the eye can receive, to a degree. This can become more important as a person ages and eyes weaken. Exit pupil is shown by the manufacturer in the product specs or calculated by dividing the lens diameter with the magnification. For example 8×20 (20÷8) equals an exit pupil of 2.5. Which is not great, but a greater magnification of 10×20 gives an exit pupil of 2, which is even worse and isn’t even an acceptable minimum. 8×25 (25÷8) gives us an exit pupil of 3.125, which is slightly better. This might not sound a great deal, but in daylight the eye’s pupil only opens to around 2-3mm anyway. More importantly, in poor light the pupil opens wider, usually to between 5mm and 9mm, less for older people, which is where a better optic with larger exit pupil will show its worth and an image will appear brighter in the poor light. However we are largely constrained by the physical dimensions of a small monocular and it will never be as good as a pair of decent binoculars can provide. The Nikon shown above has an Exit Pupil of just 2.1mm, meaning it would only be suitable for brighter conditions. On a dull day the image would be too dark to see detail, and importantly, you would not enjoy the viewing experience.
This is the maximum distance your eye can be from surface of the monocular lens and still see a full Field of View. This can be especially important to spectacle wearers where the monocular is held further away from the eye. A fold down, or twist in/out eyecup can really make a difference here so look for this feature. That, or use the monocular without spectacles, you do not need them to view things through an optic.
There are other factors to be considered but the most important have been covered above. In addition, smoothness of operation, degree of armour (if any), smooth easy focus, all are desirable features and will add to the cost.
It is almost impossible to try out one monocular of one brand next to another by another brand. Stockists either don’t carry large ranges of different brands, or if they do, seldom are monoculars part of what is carried. Having done your research and made a short list of desirables, make a ‘best informed guess’ on what might work for you. If you have done your research properly then there should be no nasty surprises when it turns up. The best thing to do is actually try out the monocular in low light, also tracking an object and attempting to focus while doing so. If it doesn’t suit you or you cannot get on with it, return it and save your money. If it does, then welcome to a whole new world…
What does Three Points of the Compass use?
I purchased an Opticron 8×20 Gallery Scope decades ago and it is that 109g ‘middle-of-the-road quality’ monocular that has most often snuck its way into my pack on longer trails. I have finished some walks where it has never left my hip belt pocket, while there have been other trails where it has frequently been used while attempting to follow the movement of butterflies, dragonflies, birds, bats, weasels, stoats, pine marten, or to simply see if that is a pub in the distance, and is it open. I will have a closer look at the Opticron and its latest incarnation in a post to follow. More recently I have been trying out a slightly heavier 8×25 option from Viking that provides impressive low light performance. More on that ‘scope in a later post. Do consider other options to those listed here, there are good alternatives.
While Three Points of the Compass continues to hanker after the eye-wateringly expensive Leica 8×20 Monovid, probably the highest quality small monocular on the market, either the Viking 8×25 ED or my old 8×20 Opticron Gallery Scope will more than suffice for those days when I like to include a handy little monocular with my gear on trail. A question for me now, do I want to branch out and try a smartphone mount with the monocular. More weight!
Three Points of the Compass has produced three other blogs on the subject of monoculars on trail:
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