A few decades ago, I’d often see ads for binoculars that featured extremely high magnifications such as 50× or 100×. A wise consumer would have known that these pairs had very little value.
However, such deceptive ads were regularly placed in magazines and newspapers, which meant dishonest sellers were successfully deceiving a lot of people.
As an enthusiast of binoculars, I‘ve bought a lot of pairs over the years. Their magnifications are all less than 10×. Newcomers might think that they’re not powerful enough, but I’m happy with them.
It‘s essential to know what the magnification numbers mean. This will help you to decide which magnification is best for you. Before buying binoculars, to avoid wasting your money, be sure to read the following explanation.
How magnification can be calculated
In binoculars, there are prisms between the objective lenses and the ocular lenses, which makes this explanation more complicated. So, to simplify, I‘ll use a telescope as an example.
The magnification can be calculated as follows:
For example, if the objective lens has a 150mm focal length, and the ocular lens has 25mm, this means the magnification is 6×.
Because of this formula, it is technically easy to make binoculars with very high magnification.
However, with binoculars, you don’t need to know this formula. To find the magnification of your binoculars, just look at the numbers stamped on them.
What does 8×42 mean?
The combination of numbers on each pair can be confusing for the uninitiated. These are part of the specifications of your binoculars. The first number indicates the magnification.
So, 8×42, 8×30 & 8×25 binoculars all magnify the image by eight times.
The number that comes after ‘x’ indicates the aperture, the diameter of the objective lenses in millimeters. So, 8×42 binoculars have 42mm diameter objective lenses.
As the aperture gets larger, the binoculars are able to capture more light. If the magnification numbers are the same, the brightness will depend on the aperture.
How close or large does the image become with 8×?
If you want to take binoculars to your favorite singer’s concert, your primary concern will be how much closer or larger the distant singer will appear. It’s helpful to know about the meaning of magnifications when deciding which binoculars to bring with you.
For example, 5× binoculars will make whatever you look at seem five times larger or closer. In other words, if an object is 100 meters away, with 5× binoculars you can see the object as if you are standing 20 meters away.
You may think that the higher the magnification, the better the image quality. That is, however, a big misunderstanding among novices.
Generally speaking, high magnifications such as 20× cause a lot of problems: a dark, blurry, shaky image, with a narrow field of view. Such binoculars are next to useless.
Nowadays, the number of these extremely high-powered, but useless binoculars I see on the market is decreasing. Unfortunately, they do still exist in places like Amazon (below).
I imagine that the buyers won’t be able to see anything well with 30×60 binoculars. To my surprise, however, it gets a 4.5 out of 5 rating. I suspect that most of those ratings are fake.
You should keep in mind that the basic ability of binoculars depends on the aperture (the diameter of the objective lenses).
The best magnification for beginners
The magnification of decent binoculars ranges from 5× to 10×. Considering user-friendliness, I recommend newcomers choose from 5× to 8×.
Besides the magnification, there are several points to help you choose binoculars for a specific purpose. For more information on how to choose the best binoculars for you, please read this article: 5 Steps To Choosing Binoculars: A Beginner’s Guide.
A few decades ago, high magnification binoculars such as 50× or 100× were commonly sold in Japan. Many consumers were duped by the outrageously high magnification numbers.
With some knowledge about magnification, they could have avoided buying such useless products.
Having a long focal distance of the objective lenses and a short focal distance of the ocular lenses can make the magnification technically very high. However, the ability to get a bright, steady and wide image mainly depends on the diameter of the objective lenses. Magnification, by itself, has nothing to do with the quality of the image.
Magnification is one of the most important factors when choosing binoculars. So, knowledge about magnification will help you find the best pair for your purpose.