Using binoculars itself is not as simple as peering through them and seeing the whole world magnified.
You need to make adjustments to it to get the kind of view you want. Now add glasses to the mix and the whole thing appears a tad bit complicated.
Adjust The Eyecups:
The lenses that are built into the binoculars that you glimpse through are known as ocular lenses and these are held by the eyecups.
You can wear your glasses without any issues once you have these eyecups adjusted so your eyes do not feel strained at all. This is precisely why the distance between those lenses and your eyes is known as eye relief, which is an important factor to consider with or without glasses.
These eyecups make sure that your eyes are a safe distance away from the lens so they can watch through the binoculars without feeling strained at all.
If you wear glasses you should retract these eyecups. Their essential purpose is to present a clear picture by blocking out peripheral light and optimizing the magnification. This can be better achieved with the eyecups retracted since then glasses will force you to have your eyes at a larger distance than when you do not have glasses on anyway.
Ideal Glasses For Binoculars:
If you simply must wear glasses due to conditions like astigmatism and know that you will need to make a whole lot of use of binoculars it is better that you consider buying glasses according to them.
This can save you a whole lot of hassle and give you an ideal binocular experience while removing some restraints. Certain kinds that you should avoid are firstly bifocals as they can give you a pretty nightmarish experience when using binoculars.
Even progressive lenses can give you a really tough time if you do not know how to handle glasses and binoculars together. The best thing would be to just get a pair that has flatter lenses.
This way they will not be sticking out and prodding your binoculars lenses with you constantly adjusting them so you can watch properly. It can also be more ideal for you to get those with a rounder profile as they too make the job much easier.
Tips To Keep In Mind:
You do not simply have to wear glasses to be able to peer through the binoculars.
If you are near-sighted the binoculars lenses will just adjust accordingly and give you the perfect view of what you want to glimpse at. However, astigmatism may require glasses to be essential and worn at all costs.
This way you can know what works for you and what does not. A little bit of experimentation and some hefty reading of the instructions that can help you make adjustments to your binoculars can really help a great deal.
This can mean ensuring that there is at least 16 mm of eye relief present before you purchase the glasses if you cannot retract the eyecups. This way you will have sufficient space between your glasses and the binocular lenses so that no terrible experiences force you into reconsidering your purchase.
Straps Are Handy:
Just get a neck strap so they can hang safely from your neck. All you have to do is lift them up to your eyes and voila the magnified view will be there for you to see. There is no need to make yourself go through additional hassles when you have such convenient alternatives at your fingertips.
Focusing The Binoculars:
The first order of business is to remove the lens caps so they do not block your view. Stash them away safely in a case so you do not end up misplacing them or forgetting altogether in the throes of your magnified vision.
Find an unmoving object and once you have your eyes set on it, lift the binoculars so you can peer through them to view it. You may have noticed a central pivot or a hinge on your binoculars. This can help you focus on the object better once you bend it until you see a solitary image. This can be done by allowing it to match the distance that exists between your eyes.
Calibrating The First Time:
The very first time that you make use of binoculars it is important to calibrate them to get the best results possible. This will involve you covering your right lens first and ensuring that the image is perfectly sharp by turning the main focus dial.
The calibration is only partly done though as you need to repeat the procedure for the other eye. You will of course need to cover it as well but this time you should turn the diopter dial instead of the main focus dial. It will likely be situated near your lens. Keep adjusting it until the image on that side is sharp as well.
Now, that your calibration is done you will not have to make too many adjustments the next time you try to glimpse at something using the binoculars.
Clean The Binoculars Every Now And Then:
Just because you treat your binoculars right does not mean that they will stay clean and pristine the whole time. Respect your possessions by keeping them clean and they will respect you in turn. Using a soft brush can be a great way to remove the blatantly present dust particles but to achieve true cleanliness you should follow through with a wet cloth and a cleaning solution. Once you are done, dry the lenses with a piece of cloth but not too aggressively. You will be able to see if there are still any smudges and marks left or not.
It is not easy to learn and get the hang of binoculars. When you have additional problems like having to learn how to use it while wearing glasses that just makes the problem escalate.
Designed in an innovative principle, binoculars provide the viewers a three-dimensional (3D) image. With an impression of depth and clarity, they produce a merged view.
History of Binoculars
The credit for the first invention goes to Hans Lippershey of Holland. However, he was certainly not the first one to invent the instrument, but he did play a major role in making the device widely recognized. It was in the year 1609 when the telescope was introduced by the great Italian scientist Galileo Galilei. He also became the first man to observe the craters of the moon through the device. He went further to discover the four large moons of Jupiter, the rings of Saturn, and the sunspots. The telescopic instrument used by Galileo was equivalent to a pair of opera glasses arranged with glass lenses in order to magnify the objects. However, limited magnification and a narrow field of view were provided through this arrangement.
During the second half of the 17th century, Cherubin d’Orleans in Paris, I.M. Dobler in Berlin, and Pietro Patroni in Milan together developed box-shaped binocular terrestrial telescopes. Nevertheless, due to poor quality and improper handling, these did not become successful.
The novel principle of using a curved mirror in the place of glass lenses was introduced by Sir Isaac Newton in the year 1704. The curved mirror gathered the light and reflected it to a point of focus. The reflecting mirrors act like a light-collecting vessel; hence, the bigger this reflecting mirror, the more light it can gather. This innovative invention opened the door to creating magnifying objects millions of times.
The first real binocular was invented by J. P. Lemiere who devised one in 1825. Following Ignazio Porro’s 1854 Italian patent for a prism erecting system, the invention of modern prism binocular began.
How Do Binoculars Work?
The key principle on which the lenses of binoculars work is refraction. Lens is defined as a glass shaped in a curved, which works to slow down and bend the ray of light when it hit the surface. Convex lens, used in binoculars, functions to bring distant rays of light into a focus. Since they converge the light rays in one place, looking through a convex lens makes the distant objects appear larger and nearer.
In binoculars, two such lenses are placed together, where the first one, the objective, collects the rays of light rays from the distant object and produces a focused image. The
function of the second lens, which is also called the eyepiece, is to pick up that image and magnify it.
However, often a crossover can be observed when light rays from a distant object pass through a convex lens, and as a result, they appear upside down. In that case, the binoculars are equipped with a pair of prisms inside them to rotate the image through 180 degrees. In this way, the objects at a distance appear near and large if we look at them through binoculars.
Optical Designs of Binocular
- Galilean binoculars: The techniques and advantages of mounting two lenses side by side for clear binocular vision have been explored in the early 17th century. During these times, most binoculars used the Galilean designed optics, that is, a convex objective was used in front of a concave eyepiece lens.
One of the benefits of these optics was producing an erect image. However, the narrow field of view and its incapability of rendering high magnification stand as major disadvantages. The Galilean optics are used in binocular surgical and jewelers’ loupes where low magnification is required. In these fields, they highlight the advantages of presenting an upright image without any additional erecting optics.
- Keplerian Optics Binoculars: These are developed much later wherein improved image and advanced magnification is attained. In the binoculars that employ Keplerian optics, the viewers can observe the enhanced and better-quality image formed by the objective lens through an ocular eyepiece lens. However, the image formed through the Keplerian configuration is inverted and to turn the image upright, different methods are used. These advanced binoculars have a wide range of applications.
- Aprismatic Binoculars (Erecting Lens Binoculars): Aprismatic binoculars, also termed as ‘twin telescopes’ employ the widely known Keplerian optics. Here, each tube consists of one or two extra lenses, known as ‘relay lenses. They are positioned between the objective and the ocular lenses. The main function of the relay lenses is to erect the image that was initially produced in an inverted way. The major disadvantage of these binoculars is their huge length. No matter how popular they were in the 1800s, they soon became outmoded after the improved prism binoculars were introduced in 1890 by Karl Zeiss Company.
- Prism Binoculars: In 1890, the binocular lenses were improved and optical prisms were added to the configuration. This added design facilitated the display of the image in an upright way up devoid of the requirement of any additional lenses. This innovative technical invention played a major role in decreasing the entire length of the instrument and producing the much-needed form of image.
Applications of Binoculars
- Theatrical Uses: Galilean opera-glass binoculars can be easily held in our hands and are used in theatres. The glasses with 7 to 12 times magnification are widely used in outdoor activities. For tourist attractions, several such binoculars are mounted on pedestal. Coin-operated binoculars are also put to application which allows the visitors to achieve a closer view of the attraction.
- Geographic Applications and Land Surveys: With the development of technologies, binoculars are no longer used for geographical data collections. In the early times, binoculars were one of the advanced instruments used in land surveys. However, field glasses are still in application today and they provide much-needed visual aid while surveying large areas.
- Bird watching: One of the popular hobbies among nature lovers is birdwatching. Since human eyes cannot suffice in observing and appreciating the detailed aesthetic appeal associated with birdwatching, binoculars come to the rescue. Binoculars with a magnification of 8x to 10x are used in this field to provide for a wider and clearer vision.
For birdwatching, the size of the objective stands as the second major consideration after magnification. The size of the objective determines the amount of light it can collect. In this case, a larger objective with a size of around 40-45mm functions better in low light. It is also helpful in looking into the foliage.
- Hunting: Hunters generally use binoculars with a magnification up to 8x that also allows improved light transmission. In these binoculars, the objectives are large enough to gather light even in low light conditions. These types of binoculars assist in spotting the animals in the dark that are too far away to spot with the naked eye.
- Military: Binoculars play a significant role in the long history of military applications. Till the end of the 19th century, Galilean optical designs were widely put in application. Soon after that, prism and Porro prism types came into use. There are some stark differences between the binoculars that are constructed for civilian use and the binoculars used in general military fields. Military binoculars are more rugged and they layered with effective weatherproofing.
- Astronomical: Binoculars with a size of 25 × 150 are generally adapted for astronomical use. The wide field of view in giant and portable binoculars are helpful for amateur astronomers in viewing comets and other celestial bodies. These types of binoculars are equipped with larger aperture objectives that increase the amount of light captured and are geared for astronomical viewing.
Interesting Facts about Binoculars
- The surfaces of binocular lenses are layered with anti-reflective coatings that effectively reduce the light that gets lost from each optical surface through reflection.
- The large craters on the Moon can be completely invisible to the human eye, but can be detected with medium-size binoculars.
- The weight of the binoculars that were used in warships was up to 10 tons.
- For controlling the hand-held binoculars from the impacts of shaking, the magnifications range from 7x to 10x.
- Most binoculars have narrow exit pupils which makes the viewer fatigued because one needs to hold the instrument exactly in front of the eyes to view a clear image.
With a rapid development in the field of technical gadgets, modern binoculars are now armed with water-proofing and anti-fogging features. Their rubberized housing makes them sturdy and rugged, while the comfortable grip and eyecups allow for a safe and pleasant viewing.