How do you focus binoculars?-Adjusting Binoculars
How do you focus binoculars? is a question I get most of the time and today, we are going to address this question in details. binoculars can be exciting to use if you know how to calibrate them properly. Each one of us has different eyes and they might see things differently.
Some people might be near, farsighted or astigmatic. These conditions affect the way and the length at which we see things. Binoculars over the years have evolved and for good. These days manufacturers of these devices have ensured that everyone can enjoy using a pair of binoculars without constraints.
We will look at how to adjust these devices.
When do You Focus Binoculars?
Binoculars that create blur images, double vision, dark shadow spots or anything that appears to be interfering with the clear vision of the image you are viewing calls for correct calibration and focusing. I am sure no one wants unclear images appearing on their binos.
Types of Binoculars Focus Systems
There are two types of focus systems used in binoculars today and the one that you will opt for will determine how best the quality of the image will be. The two types are:
- Center Focus
- Individual Focus
Let’s look at each type of focusing system separately.
How to Adjust Binoculars that have Center Focus System
Center focus system focuses both eyepieces simultaneously. Both are adjusted at the same time with the adjustment of the flywheel.
Center focus binoculars are easily identified by the focusing wheel also known as the “flywheel” in the middle of the binoculars between the two oculars or barrels where the right or left index finger can easily reach.
The second part of the center focus system is the adjustable eyepiece/diopter. Most often than not this is always found near the right eyepiece. You might find it also hidden under the center focus knob.
This type of focus is the most common in modern and traditional binoculars today, yet the least understood.
So why does the diopter come with the center focus binoculars?. In fact, the diopter allows you to focus each eye to compensate for the varying eye strengths between your eyes.
Steps of Calibrating a Center Focus Binoculars
1). Step 1
The first thing to do is if you are eyeglass wearer, eyecups should be set to their fully retracted position but if you are non-eyeglass wearer, the eyecups should be set to a fully extended position. When this is done, look through your binoculars from where the exit pupil is formed and you can see one complete, round circle and the entire field of view is intact.
2). Step 2
Hold the binoculars in hands and look at a mid to distance stationery object. Now carefully move the binoculars tubes downward or upward to get both lefts and right fields properly aligned to form a perfect circle. The interpupillary distance should be correctly adjusted for you to have a comfortable viewing. So adjust the eyepiece lenses according to your own interpupillary distance.
Looking only through your left eye or the left eyepiece of the binocular, look at your target and use the center focus to bring the image into focus.
4). Step 4
To see very clear, crisp and shape image with both eyes, you will need to do some diopter adjustment. This is to ensure you get a good image without suffering eye fatigue. Usually, adjust the diopter of the left eye first then your right eye. Don’t touch the center focus knob at all. Just keep rotating the diopter until you’ve got the sharpest image possible.
5). Step 5
Weldone!. You have focused your binoculars. You might want to take note of the settings on the scale in case you make changes later.
Individual Focus (IF) System Binoculars
This is the focus system that allows you to focus each eye individually.
To save you from repetition, the way to adjust your IF binocular is essentially identical to the center focus system.
Instead of using the center focus knob to focus the left eye, just use the diopter on the left eyepiece to focus the image. Then, do the same with the right side. Don’t forget the setting for each eyepiece – this will always be your basic setting to start off with when glassing.
Self Focusing Binoculars
Self-focusing binoculars are also known in the industry as focus free,no-focus, auto-focus, fixed focus or permanent focus. these terms are marketing strategics marketers are using to confuse people to believe you don’t need to do anything but images will just appear perfect.
No-focus and focus-free binos are low-budget versions of the IF system. They’re typically fixed somewhere between 40-60 feet. Self-focusing binoculars have wide, fixed depth of field which actually allows you to glass any target from most distances, from around 40 yards to infinity, and it will always stay in focus.
Typically these type of binoculars relies on your eyes viewing strength to focus properly. Hence, they are not often recommended for people with eyes problems
Josephine is Content Manager @ Binocularsinght.com, an Electrical Engineering Grad who loves optics. She is an Outdoor Enthusiast and a Writer who likes escaping into the mountains for hiking adventures and enjoys other outdoor activities as well.