Theatre binoculars are a type of small, compact binoculars. They are typically low magnification and designed for continuous viewing.
About Theatre Binoculars
Theatre binoculars, also known as opera glasses or Galilean opera glasses, are a type of low magnification, compact binoculars popularly used for viewing theatre, ballet, and other performances. They give the viewer better magnification for viewing facial expressions and delicate movements but do not compromise on other areas, such as field of view, as much as other binoculars. This enables them to be used for relatively long periods without becoming uncomfortable or losing information around the subject.
Like standard binoculars, theatre binoculars are composed of two tubes joined together. At one end of the tubes, where light enters, are the objective lenses. At the other end are the eyepieces, with ocular lenses which transmit the image to the viewer. In between the objective lens and ocular lens is a system of prisms that bounce light back and forth along the tube.
Some basic properties of binoculars are the ability to impart binocular vision with depth perception and the ability to orientate an image the right way up. Theatre binoculars usually have a centre control for focusing.
Choosing Theatre Binoculars
Amongst the considerations when purchasing a pair of theatre binoculars are the binoculars’ magnification, objective lens size, field of view, and level of comfort.
Magnification is the extent to which binoculars are capable of bringing an object closer to view. 5x binoculars, for example, can make an object appear five times closer. So if the object is 30 m away viewing it through binoculars can make it appear 6 m away.
This is very useful for viewing theatre productions and similar events, as it enables the actors or other performers to be brought closer to the viewer. Their facial expressions, hand gestures and other movements can all be brought into sharp focus, adding another dimension to the performance and giving viewers access to information and details they might otherwise miss.
Standard binoculars are typically 8x and 10x magnification. These levels of magnification allow distant objects, such as birds or other wildlife, to be viewed in high detail. The downsides are that the field of view is narrow, and images may have a tendency to bounce out of the frame, depending on how steadily the viewer can hold the binoculars.
For these reasons, 8x and 10x magnification are usually considered too high for theatre viewing purposes. Because they offer a narrow field of view, it might be more difficult to locate subjects or keep them in view. The viewer might also not want, or need, such a detailed view, preferring to keep several performers in view at once so as not to lose sight of the whole performance. Lower magnifications offer breadth of view as well as detail. It is also easier to hold the image steadily in view.
Magnification of between 3x and 5x is typically recommended, with 3x being the more frequently used. At 3x, the field of view is wide, and the performance can be appreciated in its entirety. It is also a low enough magnification to minimise the effects of image shake which could disrupt viewing.
Objective Lens Size
The objective lens size is the diameter across the objective lenses as measured in millimetres. It is written after the magnification, so 3x10 would denote a 10 mm objective lens diameter. Standard binoculars have objective lenses of around 30 mm to 50 mm in diameter, while compact binoculars have lenses under 30 mm. Theatre binoculars, which typically have objective lenses under 30 mm in diameter, can therefore be considered a type of compact binoculars. They are basically low magnification compact binoculars.
Objective lens diameters of theatre binoculars range from 10 mm to just under 30 mm, with 3x10, 3x25, 3x28 and 2.5x25 typical. Larger objective lenses allow in more light and are useful in low light scenes or performances. They might be especially useful in outdoor performances at night.
The exit pupil is the diameter of light that can leave the eyepiece and corresponds to both objective lens size and magnification. It is calculated by dividing the objective lens size by the magnification. 3x10 binoculars therefore have an exit pupil of 3.33 while 3x25 binoculars have an exit pupil of 8.33. The 3x25 binoculars are more suitable for use in low light. For the maximum exit pupil, the eye needs to be in line with the eyepiece.
Lens coatings minimise the amount of light lost by reflection and ensure that more light is transmitted through the tube from the objective lens to the ocular lens. Coatings may be applied to both lenses and prisms. Fully multi-coated binoculars have all optical components coated in multiple layers, while fully coated binoculars have all optical components coated in a single layer.
Style and Special Features
Many theatre binoculars have a classic style, with polished metal bodies in a variety of colours. Black lacquer, white gloss, pearl, gold, silver, and brass are all popular. Some binoculars have a more modern and minimalist appearance, but most are designed with style as well as function in mind. With a good range of elegant finishes from which to choose, the viewer can make theatre binoculars an outfit accessory as well as a functional item.
Many theatre binoculars have a coordinating holder that can usually be adjusted as required and in some cases detached. This enables the binoculars to be held in a more natural and comfortable position and therefore allow longer continuous viewing. This is a useful feature for those who like to use their binoculars for long periods at a time. Handles can usually be folded neatly across for compact transport and storage. Some theatre binoculars come with a chain or strap so they can be held conveniently around the neck when not in use.
Theatre binoculars are usually sold with a hard or soft case for protection during storage and transport. Keeping binoculars carefully stored and maintained will keep them in better condition for longer. Transporting them without a case could end up with either the lenses or body being scratched or otherwise damaged. Cleaning cloths are another useful addition.
When looking for a pair of theatre binoculars, always bear in mind aspects such as robust, durable design and high-quality optics as well as style. A lightweight construction is often preferable as it allows the binoculars to be held more easily and comfortably, but there is no need to compromise with regards to sturdiness and durability.
Find Theatre Binoculars on eBay
To find theatre binoculars on eBay, visit the home page and follow the Electronics tab to the Cameras & Photography page. Scroll down the tabs, and select Telescopes & Binoculars followed by Binoculars & Monoculars and Binoculars. Using the headings in the left hand side tabs can refine listings, filtering out those which are not relevant, but because many sellers do not specify certain criteria, it can also mean that relevant listings are also filtered out. Look at the number in brackets after each option, and this gives the number of listings in that category. If there are a large number of unspecified listings, it can sometimes be better to leave the option unspecified. On the other hand, if by browsing listings, there are no relevant items, it might be quicker to use these criteria. A useful option for theatre binoculars is the magnification. Scroll down to magnification, and select Less than 8x. Also by scrolling down further Galilean can be selected.
Alternatively, the search bar at the top of the page can be used to produce listings. Type in terms such as “theatre binoculars” or “3x binoculars” and press Search.
Theatre binoculars are popularly used during theatre productions or similar shows. They enhance the viewer’s experience of the performance by allowing more detail, such as facial expressions and hand gestures, to be revealed. However, because of their low magnification, typically around 3x, they also allow a broad field of view and so do not detract from the performance as a whole. The low magnification also means they can be used for longer periods more comfortably. Other considerations when buying theatre binoculars are objective lens size and exit pupil. Theatre binoculars usually have objective lenses under 30 mm in diameter, with typical sizes including 10 mm and 25 mm. There is some difference in these sizes, and the 25 mm pair gives a wider field of view, other factors being equal. A pair of 3x25 binoculars has a larger exit pupil and is more suitable for low light conditions than a 3x10 pair. Lens coatings affect light transmission, and fully multi-coated binoculars are best. Special features and accessories of theatre binoculars include matching holders, neck chains, and cases. Binoculars should be carefully stored and maintained to keep them in good condition. Theatre binoculars are typically designed with style as well as function in mind and are available in a range of attractive finishes.