How Do You Focus Binoculars?
If you are trying to use binoculars but something seems off, resulting in the binoculars being pretty much unusable, then the likelihood is that they aren’t quite focused right. If this is the case, then the answer to focusing your binoculars is the diopter adjustment, which is a control knob you can turn to adjust.
What this diopter adjustment does is compensate for the differences between your two eyes (as both your eyes can’t focus on the same distance at the same time!)So you essentially have to adjust this to ensure the two barrels are in proper relation, allowing the focus to be just right.
Binoculars have a central focusing knob, which is what most people use to fine-tune the focus. This knob essentially focuses both barrels for both eyes, at the same time. But apart from this, you need to adjust for the differences between your eyes, and that is why you need to use the diaper adjustment.
As a general rule, you should only have to use the diopter adjustment one time, fine-tuning the focus on your right barrel. After that is all set up, you can simply use the central knob to change the focus on the binoculars, and as it moves both barrels equally, the difference you previously set up will remain the same.
But how do you focus on one of the barrels with the diopter adjustment? Let’s get right into it! Here are the main steps you need to follow:
- To begin, start by setting the diopter adjustment at the central position, which is most often marked as the zero position. Alternatively, it might be marked with a symbol. To confirm it is in the center, try turning the ring of the adjustment both left and right, as you should be able to turn both ways from the center position.
- Next, cover up the barrel that you are adjusting. (Usually, it is recommended that you adjust the right barrel). You can do this by placing a lens cap on it, or you could also tape it with a dark surface, or even have someone hold a hand up to it so that all you can see is darkness.
- Next, you need to look at an object that is a middle distance away (like for example a house across the street or similar). It needs to be something that won’t move around. You should keep both eyes open, and use the center focus knob to focus the binoculars until you can see the object in a clear and sharp way.
It’s super important to keep both eyes open or else the process will not be precise.
- Now your left barrel will be perfectly focused, so it’s time to uncover the right barrel so that you can fine-tune the diopter adjustment to add the difference. For this, you need to keep the central knob in the same position, as you will now just be changing the right barrel adjustment.
- Uncover the right barrel and look at the same object again. You still need to keep both eyes open, to ensure the process is correct, but you should cover the left barrel so that you are looking with your right eye, as that is the one you are trying to focus.
- Turn the diopter setting on the right barrel, back and forth, until you can see the object clear and sharp with your right eye.
- Now, remove the lens cap from the left eye and look through the binocular using both eyes. The image should be clear and sharp for both eyes now!
From then on, if you focus the binoculars using the central focus knob, the differences in focus between the left barrel and the right barrel will remain, so that your eyes are well-compensated with a slightly different focus, allowing you to see sharply and clearly with both.
Most binoculars have the diopter adjustment as a ring around each barrel that can be turned back or forth in order to adjust. This way, it should be very easy to know which barrel you are adjusting, and the movement should be simple and easy to make the process fast.
However, some binoculars have the diopter adjustment at the center, next to the central focus knob. This can be a bit trickier, as you might accidentally turn the wrong adjustment knob. But with a little more care and patience, you should be able to figure it out in no time.
Also, don’t be scared to adjust the binoculars again if the focus still seems a little off. It can sometimes take a few tries, and what’s important is that the focus is as precise as possible by the end.
After that, you won’t have to worry about the diopter adjustment, and you can simply use the binoculars and adjust the central knob when needed for different distances.
With time, while you use the binoculars, the diopter adjustment might accidentally get moved a tiny bit now and then, and eventually, the focus might be off all over again.
This should not happen very often, and if it does, it might be a sign that you are holding your binoculars wrong, which is why you are accidentally moving the focus so regularly.
But if you really want to avoid this hassle, you might want to look into a fancier pair of binoculars, as some of the more advanced designs have a locking mechanism to ensure that the diopter adjustment does not move accidentally once it has been set to a precise focus.