Binoculars are a useful tool for viewing distant objects or landscapes with detail and clarity. Although they are generally a simplistic tool, there is a specific process for adjusting binoculars to ensure a clear focus and a satisfying image. The binoculars must be adjusted for both viewing distance and for differences in eyesight between the individual user’s eyes.
When binoculars aren’t properly focused, trying to see can be a lesson in futility. Oftentimes, an issue with binoculars is simply due to an improperly adjusted diopter. This article will cover some of the ways you can use diopter adjustment for optimal viewing experience.
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Typical Adjustment Options
A typical pair of binoculars has several options for focusing the view, including a central control that adjusts the primary focus and an individual adjustment control known as the diopter adjuster. These two separate functions allow you to ensure that each eye will see a focused picture through the binoculars despite potential vision differences that may exist in each eye. The view can be fine-tuned by use of the primary focus adjustment.
Diopter Adjustment Knob
If the diopter adjustment isn’t set correctly, the user may see a blurry image or even believe that the binoculars are not working properly. The diopter adjustment control may be as simple as a numbered ring around the eyepiece, so it is often an adjustment the user doesn’t notice and fails to adjust. When using a new pair of binoculars, it is important to first identify the diopter adjustment so the setting can be set for your customized visual needs.
As the video below demonstrates, it’s also important not to start moving the diopter until you’ve had a chance to look through the glass.
Simple Steps to Successful Adjustment
To adjust your binoculars for your personal use, you will want to take the following steps:
- Turn the central control to make the view as focused as possible.
- The diopter adjustment control knob is typically located on the right eyepiece of the binoculars. It should be numbered, and you can start by setting it at zero or the marking that seems to indicate the center position.
- Cover the barrel on the same side of the binoculars where the diopter control is located using the lens cap.
- Look through the binoculars at a fixed, detailed object that is approximately 100 to 200 feet away. With both eyes open, use the primary focus control to identify the clearest view.
- Switch the lens cap to the other barrel, and use the diopter adjustment to adjust the same view for your other eye.
- Remove the lens cap and look through the binoculars with both eyes. The image should be clear and sharp.
Adjusting for Different Models
Your binoculars may have the diopter adjustment in the center, and in that case, the process to focus the view is similar. Always use an object that is approximately 100 to 200 feet away to focus your view, and adjust one eye at a time.
Once the diopter adjustment is set, you can use the central focus adjustment to provide the clearest view for the appropriate distance. You should not continue to adjust the diopter control, and some high-end binoculars include a lock to prevent accidental changes to the diopter settings.
Depending on the individual feature set for your binoculars, you will also benefit from adjusting the eyepiece spacing and eyecup height, as incorrect adjustment can cause distortion in the image. It’s simple to find the clearest, most comfortable view by pushing the barrels of the binoculars together or pulling them apart. The eyecups can be adjusted for those who wear prescription eyeglasses, and simply positioning the eyecups to your needs will contribute to a clear view through the binoculars. Outdoor Life explains here how and when to adjust the eyecups.
With these few simple steps, you will learn to adjust the focus controls, enjoy clearer views and thoroughly appreciate the proper use of your binoculars for sightseeing, hunting and hiking.
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