How To Adjust A Pair Of Binoculars – 5 Effective Step From A Expert!

What makes a fine pair of binoculars? Well, a fine binocular should have the ability to produce images that are sharp, bright, and aberration free.

However, without proper adjustment, even the best binocular out there can’t meet the above expectations.

Statistics indicate that 90% of binocular users don’t know how to adjust them correctly. So, it’s no surprise that you might be having the best binocular, but with no advantage over the worst models out there.

Well, it’s time to save yourself the stress and unnecessary expenses by knowing the essential binocular adjustment tips, tips that will help you adjust for any abnormalities out there.

5 Essentials For A Perfect Binocular Tuneup

There are five essential binocular adjustments you need to master. These are:

  • Eyecup
  • Eyepiece
  • Diopter
  • Focus Ring
  • Tubes

Step 1: Adjusting The Eyecup

When you hold a binocular, the first thing to think of is becoming an eyecup master. A correctly adjusted eyecup has two advantages:

  • To provide ideal eye relief, both to persons who wear glasses and those that don’t.
  • To provide comfort around the brows and eyes.

Remember, eyecups are adjusted differently according to type. Essentially, there exist 3 different types of eyecups:

  • Fold up/down
  • Adjustable twist up/down
  • Wrap around

1. Fold up/down Eyecups

Though its popularity is on the decline, some hunters still prefer this old school eyecup. So, how do you adjust the fold up/down eyecup?

For glass wearers, simply fold down the eyecups to a fully retracted position. For non-glass wearers, set the eyecups to a fully extended position. Doing so will give you a chance to view the entire field of view.

NB: Fold up/down eyecups are more common on the low budget and entry-level binocular.

2. Twist up/down Eyecups

Twist eyecups, in most cases, come fully adjustable. Plus, twist models are very easy to use. Therefore, it’s no surprise that they’re becoming very popular among binocular users. To adjust it, simply rotate (typically in a counter-clockwise direction) such that it’s out and away from the ocular lens.

Multi-position twist eyecups make an audible sound at certain points, mostly at the mid-level and fully extended position. Fully adjustable models, on the other hand, let you stop anywhere.

NB: Some twist eyecups come with a locking mechanism to keep them in place. Also, for glass wearers, you might want to avoid pressing too hard into the eyecups lest you adjust them and lose focus.

3. Wrap-style Eyecups

You may have heard it in other names, such as the horn or winged eyecups. But there’s one thing before we go into further detail. If you’re a glass wearer, it’s recommended that you steer clear of wrap around eyecups.

Asking yourself why? Well, wrap around eyecups have a contoured design that tends to hug the eye sockets making them impractical for glass wearers.

However, hunters using them with naked eyes have a lot to benefit. For instance, the wrap-around design keeps the eyes sheltered from the wind, rain, and bright conditions. Plus, it eliminates distractions thereby improving image focus.

Step 2: Adjust Eyepiece Distance

Often referred to as the interpupillary distance, this is the distance between your eyes and the eyepiece. Remember, the focus image tends to get clearer at different distances that tend to vary among individuals.

That said, you need to adjust the eyepiece in accordance with your interpupillary distance. Here’s how to do it:

Hold the binocular steady and take a view of any distant object. While at it, move the bino tubes up and down until the left and the right fields are correctly aligned.

Step 3: Diopter Adjustment

Most bino users tend to have a dominant eye. This causes a challenge when trying to look through a binocular with both eyes. Plus, you’ll most likely experience eye fatigue. If that’s the case, then you should consider adjusting for the difference in sight between each eye for a crisp and sharp image.

But how do you adjust a binocular for both the right and left eye?

One thing to remember is that diopter adjustment is best done starting with the left eye then the right one. To adjust for the left eye, use the focus knob. To focus for the right eye, use the diopter.

Step 4: Adjust The Focus Ring

Rotate the ring to get a better focus.

Step 5: Adjust The Tubes

Ever heard of collimation? Well, this is the position where the prisms and the lenses are correctly aligned. To achieve this, you need to check if one or both tubes are out to avoid a double vision effect.

Ensure the tubes match with each other. To do this, collapse the bridge until you get a single large circle of view.


A pair of binoculars can be quite expensive. Therefore, it makes sense to maximize its use and leave nothing to chance. All these start with proper adjustment for superior images and exciting viewing experience.

So far, we’ve given you the tips to make that happen. Now it’s time to put it into practice and take your birdwatching/hunting experience to the next level.

Featured Image Credit: Eagle Optics

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