Focusing is pretty important for using binoculars to see what you’re looking at, don’t you think? Sure. But what is important to know about the focusing ability of binoculars?
Stay away from fixed-focus or focus-free binoculars as they are somewhat limiting and typically have a large close focus. Focus-free binoculars will have their focus set to the middle ground. Not ideal.
Zoom binoculars sound really cool, but avoid this type as well. Mechanically, it is very difficult to coordinate both tubes of the binoculars to have exactly the same magnification and focus. What happens then is that your brain tries to compensate for the differences that your two eyes are seeing and you will experience eye fatigue. Zoom magnification is even more difficult with higher quality optics, so the zoom type of binoculars are generally of lower quality.
More commonly you will find binoculars that have a central focusing wheel typically set between the two tubes. A thumb or finger can easily move the wheel to change the focus from near to far objects. When you test binoculars make sure the focusing knob or wheel is to your liking. If you’re not comfortable with the mechanics of your binoculars, you’ll be less likely to use them often.
Look for an adjustable eyepiece. Usually the right eyepiece can be rotated right or left to allow the user to compensate for differences between their eyes. Even if you wear corrective lenses the focusing adjustment of the eyepiece can really bring your subject into sharp focus. All you do is look at an object and focus on it with the focusing wheel. Then, rotate the focusing eyepiece to the left or right until the image is sharp. Once you make the adjustment on the eyepiece for your eyes you can leave it alone. You might have to readjust it after sharing your binoculars with a friend, but you’ll know approximately where to set it for your eyes.
