How To Use Individual Focusing (IF) Binoculars
Knowing how to use binoculars can be an exciting experience indeed. Having an understanding of a few simple procedures will ensure enjoyment.
Binoculars are available in two types, according to their focusing: The central Focusing CF and the Individual Focusing IF.
Here we will be looking at the Individual Focusing Binoculars and how to use them.
Nomenclature Of IF (Individual Focusing Binoculars)
Eyepiece lens, diopter adjustment ring, neck strap eyelet, central shaft, interpupillary scale, horn-shaped rubber eyecup, index, body (tube), and objective lens.
- Adjusting Eyecup
If you are a non-eyeglass wearer, you should set the eyecup to the fully extended position. But for as an eyeglass wearer, eyecups should be set to the fully retracted position.
Using the eyecup in an appropriate position, looking through the best binoculars from where the exit pupil is formed (eye point), the entire field of view can be obtained without vignetting.
To set the rubber eyecup: being a non-glass wearer you should set the rubber eyecup up. While as an eyeglass wearer, the rubber eyecup should be folded back.
Adjusting Interpupillary Distance (Distance between the eyepieces to your eyes)
Interpupillary distance varies among individuals. So you need to adjust the distance of the eyepiece lenses according to your own interpupillary distance.
While looking at a distant object and holding the binoculars with both hands, carefully move the binocular tubes upward or downward until both the right and left fields are correctly aligned, forming a perfect circle.
The image might be uncomfortable to view if the interpupillary distance has not been properly adjusted.
Adjusting Diopter On Bothe Eyes (Focusing)
You need to adjust the diopter if you are to look through binoculars with both eyes. If for instance you have a different visual sharpness between the right and left eyes, if without doing this you look through a binocular, the images you see will not be sharp and crisp, because one eye will see objects in focus while the other does not. Coupled with the fact that you will suffer eye fatigue.
It is usually better to adjust the diopter of your left eye first, then your right eye. To do that just focus with your left eye by focusing ring. Through the left eyepiece look at an object with your left eye. Keep turning the focusing ring until you see a sharp image of it. Then coming to the right eye, focus with the right eye with diopter adjustment ring on the right eyepiece. Look at the same object through the right eyepiece with your right eye. Rotate the diopter adjustment ring (usually located on the right eyepiece) until you see a sharp image.
Difference Between Central And Individual Focus binoculars-
While central focusing uses one knob to move the lenses in both barrels of the binocular simultaneously, and one diopter is used to balance the Hunting binocular for your eyes. While in Individual Focusing, each eyepiece is focusing separately. Both eyepieces are actually diopters with numbers for exact focusing.