When To Use A Spotting Scope Instead Of Binoculars

To the uninitiated a pair of binoculars and a spotting scope are used for the same purpose which leads to the question, why do you need both? Well, although spotting scopes and binoculars have similar functions, there are plenty of differences. Firstly we need to understand how they both work.

Spotting Scopes

Spotting scopes are far larger than a pair of binoculars but they have a far higher level of magnification. Because of that high magnification, a spotting scope will need support on a tripod to produce sharp, crisp, clear images. Of course a decent spotting scope will cost more than an average pair of binoculars but many prefer the extra magnification and of course the angled eyepiece too.

A spotting scope can be compared to a lower powered telescope that can be used during daylight hours. The difference between a telescope and a spotting scope is in strength and weight. A spotting scope is far more robust than a telescope and is usually waterproofed and lightweight too.

Due to their high magnification capabilities a spotting scope allows you to view objects that are way off in the distance without causing any disturbance of those objects. Imagine viewing a rare nesting bird close up without disturbing the nest. This is also why scopes are popular amongst hunters and digiscopers who attach a camera to the scope and get great close-up shots of wildlife.

What Are The Pros & Cons Of Spotting Scopes?

Spotting scopes allow a far closer view of whatever you’re trying to view and that view will be fairly sharp due to the size of the objective lens which allows light into the scope to illuminate the image. With an average magnification of 60x it’s possible to see objects up to 60 times larger than with the naked eye.

The optical technology used to produce a spotting scope is as advanced as the technology used to produce binoculars so a clear image is almost guaranteed. But scopes do have some bad points too.

As they only have one lens tube, you can’t see a stereoscopic image through a spotting scope. For the same reason, scopes have a narrower field of view than a decent pair of binoculars, and scopes weigh comparatively more than binoculars too.

Pros Of A Spotting Scope	Cons Of A Spotting Scope
High Magnification Levels	Narrow Field Of View
Can Be Handheld For Short Periods	Heavy
Large Objective Lens (Bright Image)	Needs Tripod Support
Angled Viewing (Easier To Share)	More Complex To Use
	Less Portability

Binoculars

Binoculars are lighter, easier to carry and maneuver, have a wider field of view and offer stereoscopic vision. But binoculars have a lower level of magnification. Binoculars can be described as two telescopes joined together giving twice the viewing power. They are also designed to be relatively robust and yet lightweight. 

A decent pair of binoculars will last you for many years without any problems and will not cost you a fortune. Of course for hand held binoculars the magnification is limited to 10x due to the natural shake which is part of human physiology and only noticeable above 10x magnification.

So any extra portability of binoculars over a spotting scope is lost above 10x when a tripod support is necessary with binoculars too.

Pros Of Binoculars	Cons Of Binoculars
Wide Field Of View	Relatively Low Level Of Magnification Compared To A Scope
Large Enough Objective Lens For Image Brightness
Fairly Robust
Stereoscopic Viewing
Easier To Carry (Lighter And Less Bulky)

Before we carry on, let’s get a basic understanding of some of the optical jargon that is always heard when discussing any optical enhancement device.

Objective Lens

The objective lens is the larger lens, the one(s) closest to the object you’re looking at. The objective lens is the only way light can enter the  binoculars or spotting scope and so the only way of brightening the image you’re viewing. The larger the objective lens diameter, the brighter the image seen through the lens becomes.

Magnification

Pretty self-explanatory this one, it’s how large or magnified the image appears through the lens. With binoculars any magnification up to and including 10x is easy to hand hold and still see clearly. Above 10x and you’ll need a tripod. By the way 10x means everything through the lens will appear 10 times larger than with the naked eye.

When it comes to spotting scopes, they more often than not have a zoom magnification which means they start at say, 20x magnification and can be increased to 50x magnification. As they start at 20x scopes almost always need a tripod support to get a clear (unblurred, non shaky image).

Field Of View

The Field of view (FoV) is the width of the image you can see through the optics at a set distance (usually 1000 metres). The wider the FoV, the easier it will be to locate whatever you’re trying to look at. A decent pair of binoculars has a FoV of anywhere between 105 to 140m@1000m. With a scope having a narrower FoV (½ as much as binoculars on average) due to higher magnification and only a single lens (monoscopic viewing).

Optical Glass

Whether it’s binoculars or a spotting scope the glass used to make the lens and the prisms is crucial to the quality of the optics. The best quality prisms are made from BAK-4 glass which is the top quality precision optical glass with the least imperfections to create a clear, crisp, bright image with great light transmission.

BK-7 glass is also used to make prisms and is still precision optical glass but with slightly more imperfections than BAK-4 glass.

The lenses themselves should be made from either ED (extra-low dispersion) or HD (high density) glass. This ensures the images produced are clear and sharp with no haloing or colour fringing. Plus have full clear light transmission.

Lens Coatings

Another important factor in the production of top quality images, the coatings applied to the lenses improve light transmission and reduce glare. There are a number of coatings available which all cover the lenses to certain degrees, we recommend FMC or fully multi-coated lenses as these are coated on all surfaces with multiple layers.

Eye Cup

This is the soft plastic or rubber edging that is attached to the rim of the eyepiece. Eye cups are adjustable by either twisting or folding up or down and help in lengthening the eye relief.

Eye Relief

The eye relief is the perfect distance between the eye and the viewing lens while still seeing the full image with no black rings or other obstacles. Eye relief is really only ever an issue if you wear glasses. If you do wear glasses look for binoculars/scopes with long eye relief which accommodate for the glasses while still keeping that full image.

Exit Pupil

This is the beam of light that enters the lens and lights up our pupil. The human eye in daylight has a pupil of between 2 to 3 mm which dilates to around 5 to 6 mm as light fades. Binoculars/scopes need an exit pupil of as close as possible to our pupil size to show us a clear image. To calculate the exit pupil just divide the objective lens by the magnification, the result is the exit pupil in millimeters.

So When Do You Use A Scope Instead Of Binoculars?

Now we’ve covered the basics. Let’s discuss when to use a spotting scope instead of binoculars. The first point here is both are useful pieces of equipment to own, binoculars can help you to locate the object you’re searching for. But to get a far more detailed look at that object, be it a bird, aircraft, boat, ship, or whatever, you’ll need that extra magnification from a spotting scope.

Just imagine you’re out in the woods, and scanning the treetops you spot what you think looks like a Lesser Spotted Woodpecker. One of the rarest and smallest woodpeckers found in the UK and also sadly, one of the fastest declining species of bird. So you’re in the woods, you’ve spotted what you think is a lesser spotted woodpecker, but you just can’t see it clearly enough through your 8x binoculars.

Train your spotting scope onto the same area of the same tree and there it is, in all its glory, it is a lesser spotted woodpecker and not the great spotted woodpecker. You can see that now because the white bars on the wings are so clearly apparent through the 20x magnification of the spotting scope. Maybe you can also spot the two forward facing and two backward facing toes too, especially if you zoom in on the scope.

That was just one example of when to employ a spotting scope instead of a pair of binoculars. You see they both have their place, and binoculars are great for scanning the area in search of whatever you’re searching for, but once you’ve found it, get the scope out and get a far closer view.

Or imagine standing on a beachhead, staring out to sea with your binoculars watching for the long awaited fly past by the Battle of Britain display team. Far off in the distance you spot the first planes coming over the horizon, quickly switch to the scope and now you can even see the pilot flying the lead plane plus all of the markings on the fuselage and even the undercarriage.

Frequently Asked Questions