Glossary Of Binoculars: Close Focus Distance

Close focus distance indicates the closest distance your binoculars can focus.

It may seem odd that some people are interested in “Close Focus” when they choose binoculars because binoculars are usually used to look at things far away.

However, the close focus distance is important to those who use binoculars in museums or for looking at insects like butterflies. They want to see things close up in great detail.

Conventional binoculars enable us to focus from as close as 2.5m, but some new binoculars are designed to be able to focus from 1.5m.

However, you should be aware that the close focus distance will vary depending on your eyesight. If you are nearsighted, the close focus distance will be shorter than that shown in the specifications.

• At museums

At art museums, areas where famous paintings are displayed are usually roped off to prevent people from getting too close. If your binoculars have a close focus distance of 2m (6.7ft) or less, you can see the paintings up-close and in detail.

I recommend low-powered binoculars with close focus distance so that you can get a wide field of view.
For further information, please see the article: How to Choose Binoculars for Museums.

• For insects

I like stargazing with binoculars, but I also like to look at butterflies on flowers. One might assume that a magnifying glass would work better than binoculars, but getting too close will frighten them away.

This is why you should use close focus binoculars. I’m sure you’ll be amazed at the enlarged images of beautiful butterflies in three dimensions.

The Pentax Papilio Ⅱ is designed for watching objects at short distances.

With ordinary binoculars, the two image circles would not come together at a short distance (see below).

This occurs because our eyes are crossed while the barrels of the binoculars stay fixed in parallel.

This is why some people prefer using a monocular, although they have to give up seeing in three dimensions.

For those who want to solve this problem, the Pentax Papilio is the best solution.

The image convergence system enables us to focus on something only 50cm away!

Also, it automatically moves both of the barrels inward depending on the distance of the object. As a result, both image circles overlap perfectly.