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Canonís 18x50s are their most powerful image-stabilised binoculars and are widely used for astronomy. But do they really show you more than the latest conventional big-eye models from premium brands?

Canon 18x50 I.S. Review

High power image stabilising binoís have a compelling use case for astronomers, but most high-powered I.S. models are really too small for astronomy. Canonís own new 14x32s join similar offerings from Fujinon and Nikon in this regard: right power, wrong objective size. Decades on, Canonís 15x50s and 18x50s are the only stabilised binoís with astronomy-sized objectives (Zeissí ridiculously expensive low-tech 20x60s aside).

When first I tried a pair of Canonís 18x50s I found them of high optical quality, but compromised in terms of the image stabiliser, which produced too many distracting effects for my liking. At the time I assumed everyone would start making high-power image stabilised binoculars and I could soon pick and choose. A decade later itís clear thatís just not going to happen.

Meanwhile, I discovered that Canonís 12x36s have been quietly revamped to create an excellent astronomy binoí. So I thought Iíd give the 18x50s a second look (and a thorough review on the night sky).

At A Glance



Objective Size


Eye Relief

15mm claimed

Actual Field of View


Apparent field of view


Close focus



90% estimated




1180g (excl batteries)

Data from Canon Ireland.

Whatís in the Box?

As usual with non-European brands, Canons Ė even expensive ones like these - have a basic box:


Design and Build

The Canon I.S. range, that even they describe as Ďbroadí, now (early 2021) has no less than five different lines, though all share a similar design and look:

        Large, high-power binoculars of semi-waterproof design, with ED lenses: 15x50 and these 18x50s

        A new line of 32mm models featuring a different type of I.S. derived from their camera lenses, including a 10x32, 12x32 and a 14x32 (see below)

       An older line including 8x25, 10x30 and 12x36, which share a similar non-waterproof design, are light weight and fairly cheap. The 12x36s are a Scope Views Best Buy for astronomy

        Premium 10x42s which are fully waterproof, have special red-ring lenses and are mainly aimed at birders

        Recent small and light-weight Ďpocketí binoculars in 8x20 and 10x20 sizes

Two smaller high-powered Canon I.S. models Ė 14x32 and 12x36.

Body and Ergonomics

The need to house the I.S. electronics mean these donít have a normal binocular body. There is no hinge Ė the body is just a solid plastic ovoid with thin, smooth armour. The result is that they look like consumer electronics, with a button on top and a battery compartment underneath.

Even if they remind me a bit of an old Sony Walkman, both external and internal build quality is very high, much like my Canon DSLR in fact.

At almost 1200g, these are heavy compared to the smaller models, though - almost twice the weight of the basic 10x30s.

Canon claim waterproofing, but given the potential for water ingress through the battery compartment and button, these wonít be submersion-proof like the best roof-prism birding binoís. You should be able to use them safely in the rain, though.

Unlike most binoculars, the non-hinged body allows these to avoid a tripod adapter: there is a standard ľ-20 thread underneath for attachment to a photo tripod.





The focuser is light, precise and free of any kind of image shift or backlash; as good as the very best in my opinion. Itís not super-fast, but for the precision needed with optics this sharp, and at this magnification with a shallow field depth, thatís not a bad thing. From close-focus of about four metres to infinity is a bit over one turn. There is plenty of focus beyond infinity, to accommodate different peoplesí eyesight, too.

In order to make these waterproof, the focusing mechanism is (unusually for porros) internal Ė the focuser moves the objectives in and out behind a sealed optical window.

You adjust dioptre (the difference in focus between your eyes) by the traditional method: twisting the right-hand eyepiece to focus it independently. In this case, it works smoothly and precisely with just the right weight (on many binoculars itís much too stiff).



Optics - Prisms

These are porro-prism binoculars (though they donít look like it) Ė the same optical design as ĎGrandad-binoísí. But if you think thatís a bad thing, itís not. In general, porro prisms give slightly higher performance than roof prisms because they transmit more light since they donít need mirror coatings.

Optics - Objectives

Canon claim that these objectives have a four-element design; Iím not sure if that includes the optical window theyíve added to the front for waterproofing.

Unlike the cheaper models, including the 12x36s and even 14x32s, these 18x50s feature objectives containing one element of special dispersion glass. Canon refer to this as ĎUDí (ultra-low dispersion). Some manufacturers use labels like ĎEDí or ĎSDí to describe much the same thing, whilst others confusingly call their binoculars ĎHDí because those special lenses give a higher definition view.

The point is that one of the lens elements is made of a special type of glass high in fluorides that gives better resistance to chromatic aberration (false colour fringing around high contrast parts of the view). With such a high magnification, this is pretty much essential.

Coatings are purple in hue (not the more neutral tone you get with high-end German binoís these days), but they are very dark and of high-quality. Combined with the inherently lower-loss porro-prism design, these should give very good light throughput for a bright view.

Itís worth pointing out at this stage that overall optical quality is very, very high. There is none of the softness you get with some high-powered binoculars. Canon make a lot of quality optics (including the objectives for Takahashi telescopes) and that experience shows here. In terms of sheer optical quality, these give nothing away to the likes of Swarovski, Zeiss and Nikon.

The insides of the barrels are machined with lots of fine baffles to kill stray light and prevent flare.



Barrels are outstandingly well baffled against stray light.

Optics Ė Eyepieces

The eyepieces are a complex design that Canon state has seven elements, including a doublet field flattener. That multi-element eyepiece design delivers a fairly wide (for binoculars) 60į apparent field of view, that translates to 3.7į true field width. In theory, these eyepieces also have decent eye relief too (the distance away from the eyepiece that the image is formed), for comfort with glasses Ö

Canon claim 15mm of eye relief (exit pupil distance), measured from the eye lens. But the eye lens is deeply recessed in the eye cup and so the effective value is more like 10mm. This means a greatly reduced field with glasses on and just isnít up to industry-leading standards these days.

Another problem is inter-pupillary distance. With no bridge, these have moveable eyepieces to accommodate different inter-pupillary distances. Thatís fine, in theory, but the big eyepieces and cups will squeeze your nose if your IPD is small, like mine.

Most premium binoculars these days have twist-adjustable eye cups with several settings. These have the old-fashioned fold-down rubber eye cups, that are much less adjustable and will probably eventually perish and split at the fold point. The eye cups are sticky rubber and are magnets for dust. They are, however, easy to fold and work well, unlike some.



Optics Ė Image Stabiliser

The biggest problem with high-powered binoculars is that the extra magnification amplifies your shakes as well, blurring the view and making it harder to see fine details. These can be used without stabilisation, just like normal binoculars, though 18x really does magnify hand-held shakes a lot. So, youíll mostly use them by activating their image stabilising function.

The image stabilisation employs a microprocessor to detect movements and then alter what Canon describe as a ívari-angle prismí to counteract them in real time. Most of Canonís I.S. binoís work this way, but not all. Canonís most recent models, like the 14x32s, have a dual-I.S. system that changes the offset between lenses instead of the flexible prism. This new system is derived from their cameras and is supposed to be higher fidelity, though my review of the 14x32s didnít convince me it was significantly better.

Other manufacturers have image stabilising binoculars which use different systems, like gyros to simply resist the shaking, or with gimbled prisms.

Like other Canon stabilised binoculars, you activate the I.S. system on these 18x50s by pushing a button. The button is quite deeply recessed and takes a firm push, but an audible click and a green light confirm the I.S. is active. Alternatively, you can give it a lighter push, in which case the I.S. is active only until you release the button again.

The first pair of these I tried, many years back, had pretty nasty I.S. with lots of unpleasant artefacts: the focus point faded in and out; colours jazzed; panning was jerky. These are much better; on first look, the I.S. seems virtually flawless: the image just steadies very positively and effectively. There is little noise and panning works fine too.

However, there are still downsides to the I.S. on these, Canonís most powerful model, that lower-powered ones like the 12x36s avoid:

1)     The I.S. can take quite a few seconds to really settle and deliver full resolution. Until then, one or both barrels can be blurred as if defocussed slightly, leaving you twiddling the focuser in frustration. Meanwhile, itís as if the optics are poor (theyíre not, the effect wears off after a while if you hold them reasonably steady). This initial defocus is very noticeable on the Moon, stars and planets, but on daytime landscapes, too.

2)     Too much shakes can re-introduce that blurring, until you and the system settle again. This means getting and retaining a perfect view for long periods can be difficult.

3)     In use, the I.S. will occasionally make a clicking noise, or suddenly jerk the view about a bit, if you stress it with too much shaking.

Overall, the I.S. works well though. Hold them steady and you are (eventually) rewarded with an impressively sharp and stable view; rest on something and the view is telescope-steady.


The 18x50s have a plain Cordura soft case, a basic strap with quite thin webbing and press-on eyepiece caps only. The case is annoying because the catch looks particularly fragile. Binoculars this costly deserve better.


In Use Ė Daytime

Ergonomics and Handling

Handling is the only area where these are noticeably worse than most current premium binoculars. That fat, bridgeless body is harder to hold than nicely sculpted barrels and the armour feels thin and less grippy than the best. That said, the focuser is superb and the dioptre adjustment simple but effective.

Weight is similar to most 50mm binoculars, although they do get tiring to hold up after a while when compared to lightweight 10x42s, for example. They do feel much heavier than some of the smaller models, like the 12x36s and 14x32s.

Itís the eyepieces that are the main comfort problem. For me they are not really comfortable with my specs off and balanced on my nose (or squeezing it), but they donít have enough eye relief to show much more than about half the field with glasses on.

In my opinion, these are not an attractive-looking pair of binoculars. If you want a certain sartorial panache to your binoís, then youíll need to look elsewhere (perhaps Leicaís beautiful leather-armoured models).



The View

Considering their high magnification, these give a very bright, sharp, high-contrast daytime view. You often do need to wait for a few seconds for the view to stabilise fully and reach maximum sharpness after you engage I.S., though. The field is wide and focus snap absolute, though the depth of field is very shallow (something to be expected with a high magnification) and so you do need to use the focuser a lot.

The high magnification, superb optics and stabilisation mean that these 18x50s resolve more than almost any other hand-held binoculars.

That high power and steady view allow you to identify birds at extreme range. I managed to ID a Kestrel soaring a kilometre or more off, just a speck with the naked eye. I watched a pair of Jackdaws mobbing a Buzzard hundreds of metres away. They would be a valuable addition to a birderís kit-bag, for when a scope isnít possible or available.

The 18x50sí capabilities donít stop with birding either. I tracked a Hawk fighter aircraft headed out over the Lake District from miles away, an extreme range to be able to make an ID, much further than any other hand held would have allowed. These would work very well for plane spotters.

For other kinds of daytime spotting, marine use, or nature viewing, these again show you more than any normal hand-held binoculars: looking across the bay to Morecambe, eight miles away, I could see individual houses, cars and trees, that are normally just vague impressions with other binoculars.

Flat field?

These Canons are advertised as having field flatteners and indeed the field is very flat for binoculars, one of the very flattest I have tested - largely free from astigmatism and curvature and with just a little distortion. Even the field edge is completely usable.

Chromatic Aberration

When discussing chromatic aberration, we have to consider that 18x is a very high magnification for binoculars (false colour worsens dramatically at higher powers, given the same optical design). So, yes, there is false colour: you can easily see it on silhouetted birds or branches, especially when focusing through - a purple tinge one side of focus, green the other.

In general use, false colour isnít a problem, though. Watching my local Jackdaws in silhouette against a dusk sky, huddling in pairs and settling into their high branches for the night, is particularly easy with these, slight colour fringing notwithstanding.

Like most high-power designs, these suffer from an increase in chromatic aberration near the field edge, but itís not as bad as some and rarely intrusive.

In Use Ė Dusk

These penetrate dusk shadows well, due to their high magnification, steady view and bright porro-prism optics.

In Use Ė The Night Sky

Canon (unusually) list astronomy as one of the possible uses for these 18x50s, so I will spend some time reviewing these on the night sky Ė object by object Ė but I will start with some general observations.

Once the I.S. has settled down, Vega yields nice round, concentric rings either side of focus Ė a sign of excellent binocular optics (even though the power is a bit low for a Ďproperí star test).

Stars remain points right to the field stop. These donít have a significantly curved focal surface or much off-axis astigmatism (that turns stars into blobs or lines, respectively), unlike many binoís. That doublet field flattener does a good job of making these one of the flattest-field binoculars of all, a great feature for astronomy.

The field of view is good for the high magnification, at 3.7į true. Itís enough to encompass more or less any region of sky you might want to view. Whilst the area left by the vignetting you get wearing glasses is smaller, itís not as much of a problem at night and still leaves enough sky area to fit in Orionís sword region, for example. Nonetheless, these donít give the gorgeously wide star fields that fine 10x50s do.

There is some faint ghosting with a bright light in the field, but that careful baffling means that working around bright lights is never a problem Ė good news for urban users.

One trick I learnt with these is to look for things by panning slowly with the I.S. enabled Ė the steadier view makes finding fainter objects easier.

The Moon

One day past full and pressing the magic button yields a host of craters Ė including dark-floored Endymion and Mare Humboldtianum behind it - along the terminator in superb, sharp detail Ö eventually. At first, though, the view is slightly soft and fuzzy. I have to wait for perhaps twenty seconds for the I.S. to settle down and the view to sharpen fully. Thereafter, a final tweak of the focuser (the sweet spot is very small) delivers a view like mounted binoculars.

On day four of the next lunar cycle, elbows resting on the roof of my car for a bit of extra support, I again get a telescope-like view with all the major features easy to pick out. The bigger craters, like Cleomedes, Langrenus and Petavius are easy, but I can make out smaller ones too - Picard in Mare Criseum and nearby Proclus with its bright rays; Stevinus, Snellius and Geminus on the terminator, floors full of black shadow. The view is perfectly sharp and full of contrast and detail, with only a little false colour around the bright Lunar limb to complain about.

I would buy a pair of these Canon 18x50s if I lived in the suburbs with nowhere to set up a scope, even if only to enjoy the Moon. Once settled, these give Lunar views much more like a telescope than any other hand-held binoculars. Most of the features in my ĎPhotographic Atlas of the Mooní are within its grasp and that steady view makes the Moon really explorable.



Venus in a dusk sky showed a little flare until the I.S. had settled for perhaps 20-30s, then almost none. Venusís brilliant white gibbous orb, at 19Ē across, was then very easy to make out, by far the best view of it I have had with binoculars. This is impressive Ė more than a few spotting scopes struggle with Venus.


With the usual caveat about waiting for the I.S. to settle down, the view of Jupiter was outstanding for binoculars. The planet appeared as a perfect disk, an unexpectedly large one due to the high magnification. There is no spiking or smearing at all. In a brightening dawn sky that lowers the contrast a bit, I could even make out a hint of the equatorial belts, a rare ability in binoculars. Jupiterís Galilean moons were super easy to track with these.


Of course, these arenít about to show you albedo marking on Mars, but even six months after opposition, when itís very small, Mars is still obviously a planet Ė bigger than the tight Airy disk of a similarly bright star.

Deep Sky

For small DSOs, the Canon 18x50s are a winner. The Ring Nebula (M57) is easier to find than with any other hand-held binoculars Iíve tried. Similarly, the Dumbbell isnít as bright as through big-eye 56mm binoculars (which gather 25% more light), but shape and definition is outstanding, really picked out from the background by the steadying effect of the I.S. The Crab Nebula (M1) is again easier to pick out than usual and shows its shape better than in any lower-powered hand-held binoculars. Bodeís Nebula, big and clear through the 18x50s, also shows more of the shape and character of its two constituent galaxies. Whatís more, the high magnification supresses sky glow and haze, helping find smaller DSOs.

Globular Clusters are easy to find and look good too; M15, right of star Enif in Pegasus, looked like a properly fuzzy star, albeit a bit dimmer than through a good 15x56. Smaller, but still obviously a globular, is M56 between Cygnus and Lyra Ė quite hard to find in smaller binoís but easy with these.

The sword area of Orion, with big and bright M42, looks Ďtelescopicí through the 18x50s, with the four main Trapezium stars easily resolved. The nebula is big and bright and shows a lot of detail, especially with averted vision; I can see hints of whorls and the Ďarmsí and central Ďspikeí of nebulosity spreading a long way into space. Still, the smaller aperture means I canít see hints of colour as well as with 15x56s under dark skies.

The news is also positive for open clusters. The Starfish and Pinwheel clusters in Auriga arenít as bright as through 15x56s, but show all their bright constituent stars and their very recognisable shapes in a way lower powers and non-I.S. just donít permit. The Double Cluster similarly isnít as bright as through 15x56s, but itís easier to see individual stars within it.

On the downside, I did notice that fainter galaxies are a bit harder to find than through 15x56s, whilst M31 is just too big for the smaller field of these.

Overall, the flat field, high magnification and I.S. make these a superb astronomy tool that excels on the Moon and small DSOs. But lack of aperture means a bit less reach than fine 15x56s and nebulosity sometimes looks less bright and detailed as a result.

Canon 18x50sí 3.7į field of view on Orion.


One possible interesting use for these is hunting and watching satellites. They have the useful property of telescope-like resolution, with binocularsí ability to pick up and track fast-moving objects. I watched a bright satellite (perhaps some Cosmos flavour) cross the sky, sweeping to follow it with the I.S. (no pun intended) engaged, and I could make out its cross-shape, formed by the fuselage and solar panels.


Testing the Canon 18x50s.

Canon 18x50 vs Zeiss 15x56 Conquest HD


The discounted price of these binoculars is very similar. Both offer outstanding value for hand-held astronomy and are obvious competitors. So how does the German engineering and bigger aperture of the Zeiss stack up against the higher power and image stabiliser of the Canons?

        Weight is similar, but the Canons are more compact

        Optical quality is similar

        Chromatic aberration levels are similar

        The Zeiss Conquests have more eye relief Ė a big factor if you wear glasses

        The Zeiss have a wider field, but the Canonsí is more perfectly flat

        The Zeiss give a wider field for panning through star fields

        The higher magnification and I.S. make the Canons much better for the Moon and smaller DSOs, able to resolve detail no normal hand-helds can

That last is the killer app here. If you live under urban or suburban skies with nowhere to regularly setup a telescope, or if you value super quick-looks between the clouds, get the Canons.


The first thing to say is that image stabilisation is no gimmick and works well, delivering way higher resolution than any normal hand-held binoculars can, especially at this high magnification. The basic optics are first rate too, giving a flat, sharp, bright and very wide field. No issue with the focuser either, itís smooth and precise.

Make no mistake, the resolution of these is a big deal. For very long-range birding, exploring the Moon, or perhaps checking out the secret aircraft on the Tonopah Test Range in Nevada from that hill south of Highway 6 (sorry, Mr CIA Man, Sir, I was just kidding), these outperform everything else: no conventional binoculars are going to reveal as much without a tripod.

So, the image stabiliser really works, but it does take a long time to settle and can occasionally make the view jerk around or temporarily blur whilst in use.

There are other issues, too. The biggest is with the eyepieces. There isnít enough eye relief to see anything like the whole view with glasses and the eye cups are the old-fashioned roll-down type. More problematic for some people is that the eyepieces are too fat and pinch your nose, if you have a small inter-pupillary distance, like me; you can get around this by folding the eye-cups down and kind of resting them on your nose, but itís not ideal. Another small issue is that the depth of field is very shallow Ė you have to re-focus a lot when you pan around during the day.

Though the build quality is high, these are a bit plasticky compared to a fine conventional binocular of similar price. You should also consider that these are essentially a piece of consumer electronics - theyíre not an heirloom the way those Swarovskis, Zeiss or Leicas could be.

But hereís the thing: if you need the highest resolution in a hand-held binocular Ė for birding, spotting or astronomy Ė these deliver like nothing else.

Do you really need a scope, but donít have the time or space? You just found the best solution currently available. Canonís 18x50s are very highly recommended, if you can live with their downsides.

You can buy Canon's similar 15x50s from Amazon here:



OR Buy Canon 18x50 IS from Wex here:


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