How To Choose Binoculars For Theaters (Best UK Guide)
If you were to travel back to the 1800s, attending an opera or an evening at the theatre was a very prestigious occasion. And in many ways for most of us it still is. We get dressed up in our best clothes, to go and rub shoulders with the socially elite.
If we actually want to see the show, we’d have to pay an absolute fortune to get seats near enough to the stage to see all of the action. Or, we could buy a decent pair of binoculars suitable for taking to the theatre. They’d need to be stylish, unobtrusive, with just the right magnification and objective lens diameter to give us the “best seat in the house” wherever we were sitting.
Back in the 1800s they solved this problem by using specially designed opera monoculars, which eventually evolved into opera glasses. Two opera monoculars joined together with a simple central wheel focussing system. These opera glasses, as they became known, were functional but also stylish to the point of flamboyance. There are still opera glasses available today for using in theatres and they still have that flamboyant flair.
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Binoculars For Theatre
The thing is, there are so many top quality brands making compact binoculars nowadays that, unless you’re a regular theatre goer, it seems a waste to just buy opera/theatre glasses that will probably only get any use on very rare occasions. A decent compact pair of binoculars will be useful in so many applications, not just going to the theatre.
What Do We Need In Binoculars For Theatre Use?
As we said earlier style plays a large part in theatre binoculars, but style without function is a blatant waste in our opinion. So they need to gather enough light to illuminate the characters on stage well enough to be seen. Small enough to not be obtrusive, with enough magnification for close up viewing, but not too much as to become problematic. Let’s break each of these points down one by one;
The choices here range from ornate opera style glasses, to modern stylish, compact, folding binoculars.
They’ll be no use at all if they don’t do the job we need them to.
- Relatively Large Objective Lens Diameter
The objective lens (one nearest the stage as you look through the binoculars) needs to be large enough to let in enough light to illuminate the stage, but small enough to not look out of place or be too heavy to hold in any degree of comfort.
- Perfect Magnification
Not enough magnification is pointless and will make it difficult to see what’s happening on stage. Too much and you’ll lose your field of view (see below) plus too high magnification can lead to shaky hands and blurry images.
- Compact & Discreet
The original point of opera glasses, and attending the opera for that matter, was to be seen. The opera glasses were ornate to the point of dazzling, with mother of pearl inlay, shiny brass handles etc, some even had semi-precious stones set into the body.
But they were also small, it sounds silly now, but anything too large was considered “vulgar” , never mind they were covered in jewels and the price could probably have fed an average family for a month. They were designed to be small for a number of reasons, to not appear overly flamboyant, not weigh too much as to be uncomfortable, and small enough to not restrict anyone else’s view.
We mentioned a few terms there that those of you new to the world of binoculars might not have heard of before. So let’s get all the technical stuff out of the way in as plain English as we can.
What Is The Objective Lens Diameter?
There are two sets of lenses on binoculars, the ones closest to your eyes are the ocular lens, and the other ones, the ones closest to the object you are looking at are the objective lens. The diameter is the length of a straight line passed through the centre of a circle which gives us the size of that circle. It’s a geometric term and you’ve probably not used geometry since you were back in school.
By doubling the diameter size of the objective lens you will quadruple the amount of light the binoculars can gather. For instance a 7×50 pair of binoculars has four times the amount of light gathering ability of a 7×25 pair of binoculars. For theatre going, we would recommend an objective lens diameter of 25mm or more.
This is because natural light will be in short supply which means you’ll be reliant on the stage lights and any auditorium lighting to brighten your image. The higher the diameter of the objective lens, the brighter the image will appear through the binocular lenses.
Why Is The Diameter Of The Objective Lens Important?
When it comes to binoculars, the objective lens diameter is important for a number of reasons, it tells us;
- The Overall Size Of The Binoculars
Binoculars are available in three size classifications which are determined by the diameter of the objective lens.
- Compact Binoculars – have an objective lens diameter of less than 30mm
- Mid Size Binoculars – have an objective lens diameter of between 30 to 40mm
- Full Size Binoculars – have an objective lens diameter of greater than 40mm
- How Much Light Can Enter The Lens Tubes
As the only entry point for light is through the objective lens, the larger the diameter of the objective lens, the more light can enter the binoculars, which in turn determines how bright the image you can see will be.
- The Exit Pupil
This is the diameter of the point of light that enters the binoculars through the objective lens. This is important because the exit pupil diameter needs to either match our own pupil diameter or be as close as possible to it. Once we know the objective lens diameter and the level of magnification we can determine the exit pupil using a simple mathematical equation. Simply divide the objective lens diameter by the magnification value, the answer will be the exit pupil in millimeters.
For instance, a pair of binoculars with a magnification of 7x and an objective lens diameter of 25mm will have an exit pupil of 3.5 because;
The human pupil diameter is around 7mm at the age of 30, it decreases every decade by around one mm so at 40 it will be 6mm etc.
What Is Magnification And How Can You Find It?
The magnification is the main reason you use binoculars in the first place, a small object is magnified through the binocular lens. Actually stamped onto the body of the binoculars you will find a set of numbers like in our earlier example, 7×25. The first number followed by the X is the magnification value with the X representing “times”. So in this case 7x, this means that everything viewed through that particular pair of binoculars will be 7 times larger than with the naked eye.
As we said earlier the second number (after the X) indicates the diameter of the objective lens. It’s these values that are needed to determine the exit pupil and they are right there, stamped onto the body of the binoculars. There are a few points that need to be considered when it comes to magnification, not just for theatre going, but for all applications. They are;
- Too High A Level Of Magnification Is Bad
As humans, we all shake when holding any object for long periods of time. The medical term is “ postural or kinetic tremor” and it just means a slight shake when holding something still. It’s a perfectly normal trait and one that in usual circumstances is not a problem at all. However when that slight shake is magnified by 12x or more, it makes the image almost unviewable.
For this reason we advise never to have a magnification greater than 10x for hand held binoculars, but 10x will be too high for theatre usage we would recommend no higher than 8x (lower is probably better, opera glasses are no more than 3x).
- The Magnification Level Affects The Field Of View
The higher the level of magnification, the narrower the field of view (FoV) this is because as you close in on an object, you lose the surroundings. This won’t be such a problem when watching a show inside a theatre but if you were attending an outdoor theatre, and you happened to be a long way from the stage, a wide FoV will improve your viewing pleasure.
What Is The Field Of View & Why Does It Matter For Theatre Viewing?
The FoV is the amount you can see through the binocular lenses from left or right while looking straight ahead. The wider the FoV is, the more you can see and for theatre use, you’ll be wanting as wide a FoV as possible, especially if you’re sitting in the back section of the theatre. If you close in to look at one of the actors’ costumes or facial expressions, obviously you’ll be narrowing the FoV but when you zoom out, it will lead to a more enjoyable experience if you can see the whole stage without having to keep moving your head.
What About The Weight Of The Binoculars?
You’ll be spending the entire evening holding your binoculars, either carrying them to and from the theatre or whilst watching the performance. So weight is quite an important factor to consider. We would recommend you stick to either compact or mid size binoculars as this will keep the weight down.
Even back in the good old days of operatic performances, opera glasses weighed somewhere around the 350g range (around ¾ of a lb in old money). Modern compact binoculars weigh around 295g so they’ll be relatively light, plus they’ll be small enough to carry in a pocket or small clutch bag.
Can You Use Opera Glasses At The Theatre?
Opera glasses were actually designed to be used in theatres, so yes of course you can use opera glasses at the theatre. If you don’t already have opera glasses however, unless you intend to become a regular theatre goer, you’ll probably be better off buying a small pair of regular binoculars that can be used for lots of other activities too.
Frequently Asked Questions
Yes, you can use opera glasses at the theatre, but if you haven’t already purchased any opera glasses a decent pair of compact binoculars will probably work out better value for money.
You can use opera glasses as binoculars, but the image would not be too satisfactory. Due to the low magnification they would not be of any use over long distances.