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 IS Review

When first I tried a pair of Canonís highest power image stabilisers Ė these 18x50s Ė I found them of high optical quality, but compromised in terms of the image stabiliser, which produced too many distracting effects for my liking. I suppose at the time I assumed everyone would start making high-power image stabilised binoculars and I could pick and choose. The best part of a decade and later and itís clear thatís just not going to happen. If you need a really high power, hand-held binocular for astronomy or specialised spotting, these still have the amongst the highest magnification of any. So I thought Iíd give them a second look (and a thorough review on the night sky).

At A Glance



Objective Size


Eye Relief

15mm claimed

Actual Field of View

3.7 deg

Apparent field of view

60.3 deg

Close focus



90% estimated




1180g (excl batteries)

Data from Canon Ireland

Whatís in the Box?





Design and Build

In terms of their outward appearance, Canonís I.S. range seems to comprise four different designs. At the bottom come the little 8x25s. Next comes their most common model Ė the 10x30 Ė and its bigger brother, the 12x36 (both of which I have reviewed). Then there are the 10x42s, which have ĎL-seriesí red-ring lenses and are supposed to be a contender in the premium birding market. Finally, there are the 15x50s and these 18x50s, with a different design again. Confusingly, which model Ďtopsí the range seems to vary between markets: for some itís the 10x42s, for others these 18x50s.

The four different designs share common features: all have a chunky plastic body; all are optical binoculars of porro-prism design (not digital binoculars like Sonyís); all have a similar image stabilising mechanism that detects hand-shake and alters the shape of a special flexible prism to compensate in real time.

There are many subtle differences between models, however. These larger models are water-resistant like the 10x42s, but the cheaper models arenít. The 10x42s are the only model to boast Canonís L-series lenses, though these 18x50s do have ED glass in their optics, whereas the cheaper models do not.

Whilst many of Canonís products are now manufactured in Malaysia, these are still made in Japan; just as with Canonís premium cameras, I think there is a small but noticeable difference in quality as the result.

Body and Ergonomics

The need to house the I.S. electronics mean these depart from the binocular norm where the body is concerned. For one thing, there is no hinge Ė the body is just a solid ovoid with thin, smooth armour that looks and feels more like consumer electronics than fine optics. There is button on top to activate the I.S. and a battery compartment underneath that takes two AA batteries.

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

If the external build reminds me a bit of an old Sony Walkman, internal construction looks outstanding. The insides of the barrels are machined with lots of fine baffles that should kill stray light and prevent flare; I have never seen a binocular this well shielded against stray light.

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




Barrels are outstandingly well baffled against stray light


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 and donít need fancy phase and 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.

The objectives contain one special glass element to reduce chromatic aberration (false colour fringing around high contrast parts of the view). Canon refer to this as ĎUDí, i.e. ultra-low dispersion, though other manufacturers use labels like ĎEDí or ĎSDí to describe much the same thing. The point is that one of the lenses is made of a special type of glass high in metal oxides (as opposed to just silicon dioxide) that gives the glass special properties when it comes to dispersing white light into its component colours. With such a high magnification, this is pretty much an essential, but I should point out that the cheaper models (8x25, 10x30 and 12x36) donít have it.

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.


Optics Ė Eyepieces

The eyepieces are a complex design with no fewer than seven elements (including a doublet field flattener). This gives a total of eleven glass elements per side (including the objectives), which sounds a lot, but is quite typical for high-end binoculars these days.

That multi-element eyepiece design delivers a wide (for binoculars) 60į apparent field of view, that translates to 3.7į true field width. Whatís more, almost all of that is usable due to the field flattener. 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.

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 is.

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. This means that hand-held binoculars inevitably blur the view, making it harder to see fine details. Image stabilisation uses some complex technology to simply iron-out most of those shakes, steadying the view and allowing you to resolve finer detail that you would otherwise miss.

Like most I.S. binoculars, these can be used without stabilisation, though 18x really does magnify hand-held shakes a lot. 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 image stabilisation works by using a microprocessor-based system to detect small movements (i.e. shaking) and then alter the shape of a special prism to offset them. Other manufacturers have image stabilising binoculars which use different systems, like gyros to simply resist the shaking, or with gimbled prisms.

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.

Further investigation suggests there are still downsides to the I.S. on these, Canonís most powerful (and so challenged) model:

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 impressively well. Hold them steady and you are (eventually) rewarded with an impressively sharp and stable view; rest on something and the view is telescope-steady. However, there are still some funny effects sometimes and the view takes up to twenty seconds to fully sharpen once the magic button is pressed.


The 18x50s have a basic cordura soft case, a typical 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.

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.

Weight is reasonable Ė similar to most 50mm binoculars, although they do get tiring to hold up after a while when compared to lightweight 10x42s, for example.

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. I watched 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.

The 18x50s allow you identify birds at extreme range, too. They would be a valuable addition to a birderís kit-bag, for when a scope isnít possible or available. The high magnification and steady view allowed me to watch a pair of Jackdaws messing about hundreds of metres away.

For other kinds of long-range 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 can 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 (including Zeissí Conquest 15x56s), 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) Ė 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 basic 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 near-limb 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.

These 18x50s really excel on the Moon.



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 is outstanding for binoculars. The planet appears 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. Jupiterís Galilean moons are, of course, 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 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.

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.


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.


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 higher magnification and I.S. make the Canons better for the Moon and smaller DSOs

        The Zeiss give a wider field for panning through star fields

        The larger aperture of the Zeiss make finding faint DSOs slightly easier and shows a bit more detail in some, like M42.

If you live under urban or suburban skies with nowhere to regularly setup a telescope, get the Canons. If you have darker skies and/or own a scope for smaller DSOs and the Moon and planets, buy the Zeiss.


The first thing to say is that, even more than for lower power I.S. designs, the stabilisation is no gimmick and works well, delivering higher resolution than any normal binoculars can unless tripod mounted. 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.

One last moan is that though the build quality is high (especially inside, with lots of careful baffling), these do look 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 the similar 15x50 model here: