Distance Viewing

Posted by Alicia Baucom on Apr 24th 2020

The first magnifier constructed for scientific purposes is believed to have been designed by the English philosopher Roger Bacon (circa 1220-1292) sometime during the thirteenth century. Most magnifying glasses are double-convex lenses and are used to make objects appear larger. Today our magnification options are vast in both types of magnifiers and the rate in which they can enlarge an object. This blog will look at three basic options to include the monocular, binocular, and electronic magnifier.


Both binoculars and monoculars are intended for long-range observations. However, you will find a few differences while making use of each one. The biggest difference between a monocular and binoculars is how they look as well as how they are being used. Two reasons you might choose a monocular over binoculars are cost and portability. When you compare a monocular with binoculars of the same specs, you will usually discover that monoculars are available at a generally lower price tag. Plus, since they are both lighter and smaller than binoculars, a monocular provides the benefit of being easier to carry around. While binoculars tend to come with a neck strap the monocular usually comes with a wrist strap. If you have arthritis or other conditions which hurt your hands or wrists, you may not want to wear a wrist strap. Even people with healthy wrists usually do not find a wrist strap as comfortable as a neck strap. In terms of ease of use monoculars are straightforward. There are only one lens and one focus to adjust. That lets you work very quickly in most situations. Plus, since they do only have one lens, they are easier to maintain than binoculars. Further information comparing monoculars and binoculars can be found at Optics Mag or this binoculars vs monocular article. ILA’s featured monocular is the 4X12 Monocular.


Binocular Insight states that binoculars, also known as field glasses, are two telescopes which are usually mounted on a single frame aligned side-by-side. They provide magnification for distant objects. They are handheld devices with each telescope dedicated to one eye. Most binoculars come with a neck strap making them easier to carry around. Focusing a pair of binoculars can take some practice but once figured out can be done quickly. The way binoculars are designed is so you can easily adjust the focus of the telescopes by using a one hand thumbwheel which is called the central focus adjustment. Once the central focus is adjusted, one of the two eyepieces can be further adjusted to compensate for differences between the viewer’s eyes. This is usually accomplished by rotating the eyepiece of each mount. Unlike a monocular, binoculars can provide a three-dimensional image. Binoculars are designed to be used with or without glasses. Most manufacturers allow for corrective lens in their designs by adding extra focus ability or larger eye relief. Nightskyinfo provides an in depth look at what the numbers on binoculars mean. All binoculars are described by using a pair of numbers, such as 7×50 or 8×30. The first number, including the x, represents magnification or “power”. This tells the degree to which the object observed is enlarged. For example, a 7x binocular makes an object appear seven times closer than when viewed by the naked eye. The second number in the two-number code is aperture, the most important specification of binoculars if you plan to use them for astronomical observations. It represents the diameter of each of the objective lenses (the lenses furthest from your eye), given in millimeters. Therefore, 7×50 binoculars have objective lenses 50 mm in diameter. Aperture is so important because it determines the light gathering ability of your binoculars. Most celestial objects glow very dimly, so a large aperture becomes much more important in low light conditions. For example, 35 mm binoculars will do great when you watch a baseball game on a sunny day, but when used to observe the night sky you will find that they are pretty useless compared to typical 50 mm binoculars. ILA’s featured binocular is the 2.8X Sports Spectacles.

Electronic Magnifiers

The American Foundation for the Blind has a three-part series discussing electronic magnifiers. People with low vision have more choices than ever when it comes to magnification. You can choose from full-sized desktop electronic magnifiers (once called CCTVs), portable units that are small enough to fit in a laptop bag, and handhelds you can tuck into a pocket or purse. Part 1: Identify Your Priorities: This article looks at such things as portability, features, and cost. You will learn how to ask the right questions, not just about products you're considering, but about how you will use a magnifier in your daily life, at work, at school, at home, or on the go. In this first article, the focus is on you, the potential magnifier buyer, and how understanding your priorities is key to making a good purchase decision. Part 2: Larger Magnifier Systems, Specs, and Features: This second article will take a deeper dive into the world of desktop and transportable magnifiers, explaining how their components work together, and guiding you through the most important specs and features. Part 3: Handheld Magnifiers: Finally in this third article, the focus is on electronic magnifier products with the goal of helping you identify the features you need, and answering the question: given so many options, who needs a standalone electronic magnifier, anyway? If you are in the market for a handheld magnifier, ILA is currently featuring the Explore 8 Handheld Electronic Magnifier. To see what’s currently on sale at ILA please sign up for our newsletter, view our Facebook page, follow us on Twitter, or visit our website.