Your binoculars will only work to its full potential if you know how to adjust it. You will be surprised at the number of people who take back their new binoculars to the shop and demand for a refund; simply because they think what they bought is not what they wanted. The secret is the adjustment.
Understanding how to adjust binoculars will make a huge difference in the field.
Adjust the eyecup—turn and slide
This should be the first thing you do when you hold your binoculars. Adjusting the eyecup ensures you have a comfortable experience with this tool. If you don’t wear any eyeglasses, the eyecups should be set to the fully extended position. However, if you wear eyeglasses, you should set the eyecups to the fully retracted position.
The main challenge most people have when they adjust the eyecup is that they never get a chance to see the entire field of view. But if you use the appropriate eyecup position as described, and look through the binoculars from where the exit pupil is formed (referred to as the eye point), you will be able to enjoy the entire field of view and without vignetting.
Adjust the distance between the eyepieces and your eyes
This distance is referred to as the interpupillary distance. It varies among individuals as we see things clearer at different distances. You should adjust the distance of the eyepiece lenses according to your interpupillary distance. Here is how you should do it.
Make sure you hold the binoculars with both hands to have a steady adjustment. Take a view of a distant object and while at it, carefully move the binoculars tubes upward or downward until you correctly align the left and right fields. So you should form a perfect circle. You will notice that sometimes the image becomes uncomfortable to view, this means that the interpupillary distance has not yet been properly adjusted.
This means adjusting differences between the sight of each eye. This sort of adjustment is supposed to be performed if you wish to look through the binoculars with both eyes. There are people with different visual acuity between right and left eyes. If you happen to be one of them and look through the binoculars without doing this, you may not be able to see crisp and sharp images. This is because one eye will see the object in focus while the other will not. When the worse happens, you will experience eye fatigue.
Tip: it is important that you first adjust the diopter of your left eye before you do the same to the right eye.
The focusing ring
This part of the binoculars allows you to focus on an object better. You can adjust it by rotating the ring. If the diopter has already been adjusted, turn the focusing ring to focus any time you change the object viewed.
Binoculars work great for spotting things like game on road trips, or deer from your tree stand. However, if you’re looking to spot things much farther out, we recommend investing in a high end spotting scope.
Adjusting the tubes
You will experience eye fatigue if your binoculars are out of collimation. Collimation is simply a word used to refer to the lenses and prisms being optically aligned on the same axis.
When one or both the binocular tubes are out, you will get a double vision effect since they won’t be matching up with each other. So you can collapse the bridge until you see a single large circle of view.
The best way to perform this adjustment is by looking at an object that has a straight edge like a ledge or a power line. Slowly pull apart your device then take a keen note of the straight edge. If your image looks the same and the edge is continuous then it means that your alignment is perfect. Your tube is out of collimation if the edges separate into two.
That is how easy it is to adjust your binoculars. Also, remember to make the neck strap as short as possible so that the above adjustments can make sense. The longer the strap is, the more your binoculars will bounce and the harder it will be using this device. If all of these adjustments fail then you can consult the manufacturer.