United States



Binoculars Anatomy

Binoculars are grouped based on their focus type; CF (Center Focus) or IF (Individual Focus). Read below for a general overview of some basic features.

CF (Center Focus)

[photo] Techno-Stabi Series TS16x28 Binocular


  1. Eyepiece Lens・Eyecup
  2. Dioptric Adjustment Ring
  3. Focus Knob
  4. Binocular Body
  5. Objective Lens
  6. Strap Attachment

IF (Individual Focus)

[photo] MT Series 7×50FMTR-SX Binocular


  1. Eyepiece Lens・Eyecup
  2. Dioptric Adjustment Ring
  3. Diopter Scale
  4. Central Axis
  5. Objective Lens
  6. Strap Attachment

Using Binoculars in 4 Steps

To ensure a clear view of your subject through binoculars, it's crucial to follow the correct preparation steps. Here, we'll explain the four essential steps you should take before looking through your binoculars:

  1. Eyecup Adjustment
  2. Interpupillary Distance Adjustment
  3. Focus and Dioptric Adjustment
  4. Proper Holding Technique

1.Eyecup Adjustment

The eyecup is located at the binocular's eyepiece. By setting the eyecup position correctly and aligning your eye with the exit pupil (eye relief), you can view the entire field of vision without any distortions. There are two types of eyecups, each with different adjustment methods.

Foldable Eyecup
[photo] eyeglass wearers (folded)/non-eyeglass wearers (extended)

Fold the eyecup of the binoculars to the fully folded or extended position.

Twist-Up Eyecup
[photo] eyeglass wearers (shortened)/non-eyeglass wearers (extended)

Rotate the eyecup to adjust its height. The click mechanism allows you to find the ideal position easily.

2.Interpupillary Distance Adjustment

[photo] Step 2: Interpupillary Distance Adjustment

Interpupillary distance varies between individuals and refers to the distance between their pupils. Move the binocular's hinge to adjust the binoculars for your specific interpupillary distance.

[photo] Luminous flux (Exit pupil)/Blackout

To check for correct adjustment, adjust until the image circles in the view align and merge into a single image circle.

[photo] OK/blackout (darkening)

Note: In binoculars with a smaller exit pupil diameter, even a slight misalignment between the optical axis and your pupils can cause blackout (darkening) of the image.

3.Focus and Dioptric Adjustment

To obtain a sharp image, both focus and diopter adjustments are necessary. People often have different visual acuity in their left and right eyes. Without adjusting the diopter, the image will be in focus for one eye but not the other, resulting in a blurry and unclear view. There are primarily two focus mechanisms, each with its own adjustment method.

4.Proper Holding Technique

[photo] Step 4: Proper Holding Technique Bad/Good
  1. Hold the binoculars firmly with both hands, but avoid gripping them too tightly as it may cause your hands to shake. If you won't be moving the binoculars while using them, using a tripod can help prevent any shaking or blurriness.
  2. Place the eyepieces against your eyes, rest your elbows against your body, and look through the binoculars without raising your arms. To prevent dropping the binoculars, make use of the strap provided.
  1. If there are trees, a stand, or a wall nearby, you can lean against them or rest your elbows on them to reduce shaking or instability.
  2. If there is a landmark or object near your target, first locate the direction of your target and the landmark using your naked eye. Then, use the binoculars to observe the landmark while searching for and adjusting your focus on the target.

Basic Terms and Additional Information

Here you will find a list of terms used in binoculars and information about the specifications table