How to Calibrate Binoculars

I have taken may people out on safari and seen many of them use their binoculars. One thing that I have noticed, even by those who have a really great pair of binoculars is that there are a lot of people who don't not know how to calibrate them to make up for the difference between their eyes and even some who don't correctly focus their binoculars. It seems a shame to me to spend a large sum of money on a quality pair of optics and then not be able to enjoy them properly because they are incorrectly set up to suit your vision.

Most people who have a big difference in vision between their left and right eyes and who don't know how to correctly adjust their binoculars to allow for this eventually stop using their binoculars, incorrectly assuming that there is a problem with their equipment because of the blurry and out of focus image it produces for them.

Focusing binoculars or more correctly calibrating them to suit your particular vision and the difference in your left and right eyes is easy, only needs to be done once and only takes a few seconds, and it can turn using your binoculars from a frustrating experience into the eureka moment of "wow I wish I had known this before!"

Type of Focusing Mechanism

So to start and to correctly calibrate your binoculars, it first depends on which type of binoculars you have and it's focusing mechanism. The most common type, is the "center focus" type of binoculars. This is where your binoculars will have a knob in the center of them to focus on your subject (focussing wheel) and an adjustment ring (Diopter Adjuster) that is usually located on either the left or right barrel of your optics near the eyepiece. Please note that it can also sometimes be located on the central focusing wheel itself as either a sperate ring or to adjust the setting you need to pull out the focusing wheel a little to engage it. (It is usually marked with the following: - 0 +)

So here's how you calibrate centre focus binoculars for your eyes:

So before you can enjoy your optics, you need to first need to set them up for your vision (your eyes). This only needs to be done once and from then on it is only a matter of focusing on the subject depending on how near or far away it is from you using the central wheel:

• If the diopter adjustment ring is on the right barrel, start by shutting your right eye and leaving your left eye open (do the opposite if it is on the left barrel) - If you prefer, you can also just cover the end of the barrel with your hand. If the diopter is located on the central focusing wheel, refer to your manual to establish which barrel it affects, but it is usally the right one.
• Keeping your eye shut, use the center knob to focus on an object about 8 - 10 meters away (approx 30ft) until it becomes sharp.
• Open your right eye.
• Next, shut your left eye and leave your right eye open
• Now look at the same object and turn the diopter ring until you are also clearly focused on it.
• Look through the binoculars with both eyes open, and you should have a clear, crisp view of the object. Done! The binoculars are now correctly calibrated for your vision.

You see, easy peasy and honestly it will make a huge difference to the enjoyment of your binoculars. If that all still seems a little complicated, a demonstration may help, check out the videos below showing you just how easy it is focusing binoculars:

Video Demonstrating How to Calibrate & Focus Binoculars
Below is an excellent video created by the guys at Vortex Optics that clearly demonstrates how to correctly calibrate your optics to your vision on binoculars that have the diopter adjustment ring located on one of the barrels as well as ones that have it located on the central focusing wheel:

So far we have talked about how to focus The "center focus" type of binoculars, but what other types of binoculars are there?

Self Focusing Binoculars
If you don't want to have to focus your binoculars at all, you could try using a pair of so called self focusing binoculars also sometimes known as focus free binoculars (they are not really self focusing at all, more of a permanent focus system) - for more take a look at my article on: Self Focusing Binoculars.