Canon Binocular 18x50 IS

Canon’s 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 

When first I tried a pair of Canon’s highest power image stabilisers – these 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. 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 it’s clear that’s 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 I’d give them a second look (and a thorough review on the night sky).

At A Glance

Design and Build

 Body and Ergonomics

 Focuser

Optics - Prisms

Optics - Objectives

 Optics – Eyepieces

 Optics – Image Stabiliser

 Accessories

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 – 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.

It’s 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 don’t have enough eye relief to show much more than about half the field with glasses on.

Weight is reasonable – 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 bino’s, then you’ll need to look elsewhere (perhaps Leica’s 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 birder’s kit-bag, for when a scope isn’t 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 isn’t 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 Zeiss’ Conquest 15x56s), these suffer from an increase in chromatic aberration near the field edge, but it’s not as bad as some and rarely intrusive.

In Use – Dusk

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

In Use – 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 – object by object – 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 – a sign of excellent binocular optics (even though the power is a bit low for a ‘proper’ star test).

Stars remain points right to the field stop. These don’t have a significantly curved focal surface or much off-axis astigmatism (that turns stars into blobs or lines, respectively) – unlike many bino’s. 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 3.7° true. It’s 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, it’s not as much of a problem at night and still leaves enough sky area to fit in Orion’s sword region, for example. Nonetheless, these don’t 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 – good news for urban users.

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

Satellites

One possible interesting use for these is hunting and watching satellites. They have the useful property of telescope-like resolution, with binoculars’ 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 – a big factor if you wear glasses
• The Zeiss have a wider field, but the Canons’ 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.