You can’t get the best out of your binoculars until you know how to focus binoculars or calibrate them properly. The biggest issue I’ve noticed is that people confuse binocular focusing with turning the focusing knob. This is just a part of the focusing process and it is not complete until you calibrate the binoculars according to your myopia.
Everyone has different eyes, one eye sees better than another, and some of us face nearsightedness, while others are struggling with farsightedness. All these factors make binocular focusing a little more complex than we think. If you want to maximize your experience with binoculars, it is crucial to learn how to focus binoculars, and here is everything that you need to know.
Table of Contents
How To Focus Binoculars Correctly With Simple Steps
Before we start discussing how to focus binoculars properly, it’s crucial to understand the anatomy and the types of focusing systems in binoculars. Generally, there are two focusing systems:
- Center Focus system
- Individual Focus System
Center Focus system
The center focus system is the most common system found in binoculars. This focusing system consists of a focusing wheel located in the center and a diopter. The center focusing wheel or knob is usually located between the barrels from where it can be accessed with either left or right index fingers. The Center focus system on binoculars is a lot easier to understand than separated or individual focusing. The center focus knob allows you to move the lens simultaneously and adjust the focus at both knobs.
This is usually a big wheel with a knurled or well-serrated grooved for a well-controlled operation. This step makes the binoculars to use even with the gloves on making them perfect for remote applications like hunting. Now come to the second part of the center focus binocular system called the diopter. It is an adjustment ring that is mostly located on the right barrel. Unlike the center-focus knob, this eyepiece/diopter adjusts the focus on one barrel independently of the other.
In this way, it allows you to compensate for any difference between both of your eyes and lets you calibrate the binoculars as per your myopia. In most cases, it is located on the right barrel, but in a few binocular models, it comes with center focusing knobs. It can be in front of the knob, behind the knob, or hidden or fully integrated with the center focus knob. The diopter knob has a simple scale on it “-0+”.
How To Focus Binoculars with the Center Focus System?
Step1 – Adjusting The Eyecup
The first thing you need to do is to adjust the eyecup. Eyecups allow you to fix the binoculars around your eyes. If you wear glasses you need the eyecup retracted but if you don’t wear glasses you will get a better fit with an extended eyecup. In order to extend or raise them up from the body you need to turn the eyecup counterclockwise. However if you want a broader field of view or wear glasses, turn the eyecups clockwise to tighten them against the binocular body and keep them retracted.
Step2 – Grip Binoculars and Adjust the Barrel Center
Hold the binoculars in the right position with maximum eye relief. Bend the binoculars up and down from the center so that you can fit the eyepiece perfectly on both of your eyes. For perfect calibration of the binoculars, you need to hold the binoculars with proper IPD distance. Make sure you can see one circular image and that your field of view is intact.
Step3 – Adjust Center Focus Ring
Once you are done with the eyepiece adjustment it’s time to focus the binoculars as per your eyesight. For this, you need to find a stationary object at a mid to long distance within your field of view. Ideally, it should be 30-40 feet away from you. When you look through binoculars the image appears blurry in most cases and you need to focus. Here is how you can do it.
Step4 – Cover The Right Lens And Focus With the Left Eyes
- You can tape up a piece of paper over the right objective lens.
- Also, you can do it by just closing your right eye or covering it with your palm.
- Looking through your left eye and objective lens try to focus on your target.
- If it appears blurry, turn around the focus ring to get a well-focussed sharp image.
- The center focus ring simultaneously adjusts the focus for both of your eyes.
Step5 – Cover The Left Lens And Focus With Your Right Eye- Calibration
- Once the image is clear for your right eye it’s time to focus binoculars for your right eye.
- In most binoculars, the diopter is located in the right objective lens.
- Now tape up the left objective or close your left eye and start looking through your right eye.
- Turn the diopter ring to get a sharp well-focused image.
- Do not touch the center focus knob in this step.
- Then turn the diopter rings in a clockwise or counterclockwise direction until you get the sharpest possible image.
Step6 – See Through Binoculars
Now remove the cover from the left objective or open your left eye and see through the binoculars with your both eyes open. If the binoculars are calibrated and focused perfectly, they should feel comfortable and the object should appear sharp, clear, and well-focused. If there is even a slight blurriness, you need to review the center focus and diopter ring adjustment.
Remember diopter adjustment is a one-time adjustment and you don’t need to focus it every time until another person with different vision strength sues the binoculars. However, center focus adjustment depends upon the distance and size of the object and every time you try to focus on a new object you need to adjust this knob.
All advanced and conventional binoculars come with markings on them. After calibrating the binoculars for your vision, note down these markings so that you don’t have to go through the process again if the calibration settings are accidentally changed or someone else has used your binoculars.
How To Focus Binoculars If the Diopter Adjustment Is Located In Front Of the Focussing Wheel?
The above guide explains the standard diopter adjustment that is located on the right barrel of the binoculars. But if the diopter ring is located in front of the center focus ring you don’t know to which barrel it is connected. In most cases, it affects the right barrel but the opposite case is also possible. So I recommend you to go through the user manual to see if the diopter is connected with the right barrel or left barrel.
If the diopter ring affects the right eye you need to adjust the center focus knob with your right eye closed and the diopter knob with the left eye closed. If it affects the left barrel, do the opposite of it. Choose a stationary object in your field of view at a distance between 30-40 feet.
- Cover your right eye and look through your left eye. Looking through the left eye turn the center focusing knob to get perfect focus for the desired object.
- Now it’s time to calibrate the binoculars as per your vision.
- Cover the left objective bell by taping it up.
- Looking through your right eye, try to focus on the object.
- Turn the diopter ring until you get the sharpest image possible. Make sure you don’t move the center focus knob while rotating the diopter ring.
- Now, look through the binoculars with your both eyes open. If you have done everything right, the object you wanted to focus on will appear clear and sharp to you.
How To Focus Individual Focus Binoculars
Unlike center-focus binoculars, you need to focus both eyes separately in individual-focus binoculars. Individual focus binoculars are also known as fixed-focus binoculars, focus-free binoculars, self-focusing binoculars, or permanent focus binoculars. Terms like Auto-focus and self-focusing can be misleading for some people.
Actually, there is no such mechanism in these binoculars that can adjust them for automatic focus. You need to focus and calibrate the binoculars manually. Fixed-focused binoculars only have a diopter and there is no center focusing knob. These binoculars are factory-set to be focused within a given field of view.
There is no need to adjust the knob to focus on the objects located at varying distances. These self-focusing binoculars use special optics that use your eyes and natural sight abilities to focus the objects located at various distances within a given field of view. However, you still need to calibrate each eyepiece to compensate for the difference between your eyes. Individual focus binoculars come with two diopter rings on both barrels. Here is how you focus the fixed-focus binoculars:
- Hold and grip the binoculars on your eyes with maximum eye relief. Select a stationary object located 30-40 feet away.
- You can calibrate for either the left or right eye first.
- When you want to calibrate the right eyepiece to focus the image, blindfold the left eyepiece or simply keep your left eye shut.
- While looking through the right eyepiece, rotate the diopter ring on the right barrel. Keep on rotating until you get the perfect focus of the object.
- Now cover the right eyepiece or close your right eye and look through the left eyepiece.
- Rotate the diopter knob on the left barrel and try to focus the image.
- When you get a sharp or clear image with maximum eye relief your binoculars are perfectly calibrated.
Frequently Asked Questions
Which eye do you focus first on binoculars?
If the diopter ring is on the right barrel you first focus your left eye on the binoculars and vice versa. If the diopter is on the right side, close your right eye and look through the left eye. Use the center focusing ring to get a perfect focus for the desired object in the field of view.
Why can’t I focus on my binoculars?
The biggest reason why people fail to focus binoculars is that the diopter is not perfectly calibrated. The diopter ring focuses on one barrel allowing you to compensate for any difference between vision strength in both eyes. Diopter calibration depends upon your eyesight and it is a one-time adjustment. If you are unable to use binoculars make sure the diopter ring is calibrated according to your version’s strength.
Do you put binoculars up to your eyes?
The eyepieces on the binoculars are attached together with a center hinge. You can bend these eyepieces up and down or in and out from the center. Spread the eyepieces to the maximum, put the binoculars up to your eyes, and bend the eyepieces in and out until you get a perfect fit.
How do I know if my binoculars are out of alignment?
The first sign of binoculars misalignment is loss of eye relief. Your brain and eye muscles have to strain to focus on an object. You may see double objects, images moving, or sometimes fighting with each other.
How does the focus work on binoculars?
There are two types of focus systems on binoculars, center-focus binoculars, and individual-focus binoculars. In center-focus binoculars, you adjust the center focus ring followed by the diopter ring allowing you to focus both eyes simultaneously. In individual-focus binoculars, you have to focus both eyes individually.
Wrapping Up
So now we can safely conclude that focusing the binoculars is more than just turning the focusing knob. You need to focus, calibrate and adjust to make the most of your binoculars. Diopter settings are the most crucial part of the whole process. Since these settings are permanent I highly recommend you take some time out and calibrate your binoculars in the best possible way. Once the diopter settings are perfect, it won’t take you more than 15 seconds to focus on various objects in the field.