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Mid-sized Binoculars
and

Eye Relief

from "Hands-on field Tests"
in Bird Watcher's Digest, January, 2005
Michael Porter Diane Porter
by Michael and Diane Porter

A binocular that makes you feel as if you're looking through soda straws is no fun at all. Eye relief may be the most important consideration of all for a glasses wearer -- especially with smaller binoculars.

EYE RELIEF

Before you rush off to buy mid-sized binoculars, please consider the matter of eye relief. Bright as the mid-sized binoculars were, some our glasses-wearing judges found they couldn’t see the whole picture through them. “I feel like I’m looking through a pair of tiny tubes,” one woman remarked. “Or like someone has painted a black ring around the lens, so I can’t see the edge of the picture.” She was experiencing the limitations of the binocular’s short eye relief.

Eye relief is the distance from the eyepiece to the point where you can see the whole picture. People who wear glasses often have trouble using binoculars, because their glasses hold the binocular’s eyepiece too far away from their eyes. It’s a problem with many binoculars, but particularly with smaller ones.

In recent years, manufacturers have begun to address this problem in full-sized binoculars. They’ve increased the eye relief and have developed eye cups that have click stops so that the viewer can dial the precise amount of eye relief needed. However, most mid-sized binoculars could still stand improvement in eye relief. In our tests, most of the glasses-wearing judges experienced at least some limitation in their field of view when using the mid-sized binoculars. Furthermore, the eye relief situation is worse with 10x than with 8x binoculars, because higher magnification requires an eyepiece with a shorter focal length, and that results in shorter eye relief.

People who need glasses but do not have astigmatism can look through binoculars without their glasses, adjusting for their nearsightedness or farsightedness merely by focusing the binoculars. For them, one solution is to take their glasses off before raising the binoculars to their eyes. It’s a technique with drawbacks—one of which is missing the bird while fooling around with the glasses. Of course, if you wear contact lenses or don’t need glasses at all, the eye relief issue won’t matter at all.

It makes a difference how a person’s glasses fit. Eyeglasses that fit close to the eyes offer less interference than glasses that ride far out from the eyes. Some people who wear glasses simply purchase a special pair of glasses for birding. Glasses with small lenses can fit snugly under the brows, almost touching the eyelashes, and allow the binoculars to rest close to the eyes. That may be enough to put the binoculars at the proper distance for the person to see the whole picture.

Bifocals can make viewing through binoculars tricky, as the part of the image seen through the bifocal section won’t be in focus at the same time as upper part of the image. Experienced binoculars users position their binoculars to that they can look only through the main part of their glasses. Non-line or progressive bifocal glasses make it almost impossible to focus binoculars. If you’re getting special glasses for birding, be sure to get “line bifocal” glasses. It may also help to request that the bifocal be a small section at the bottom of the glasses, just enough for consulting the field guide.

It is challenging, but not impossible, to design mid-sized binoculars with long eye relief. It requires extra glass in the eyepiece. One manufacturer told us that his company had not opted for long eye relief in its high-end mid-sized binoculars because they considered non-glasses wearers as their primary customers for the product. We think that the birding marketplace is likely to change all that. In this era, many people have the leisure to pursue birding in later years of life, when they’re likely to need glasses. For this glasses-wearing segment of the population, eye relief is an important issue. And it’s an opportunity for manufacturers.

By way of example, the Celestron Noble 8x32 was one of the best in eye relief of all the binoculars we looked at. With its eye relief of 20mm, it affords the full field of view, or very close to it, even to glasses wearers. The new Zeiss 32mm Victory FL also admirably addresses this market. We look forward to more mid-sized binoculars with this capacity.

Mid-sized binoculars have much to recommend them. For travel, when weight and space are at a premium, the smaller binocular may make the trip when the larger one would get left at home. Furthermore, many people with small or delicate hands find the mid-sized binocular more comfortable than a full-sized model. They’re also good for children who are interested enough in birding to need a good binocular.

OK, let's look at the reviews of specific mid-sized binoculars.

Continued
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Celestron Noble 8x32
Sharp-shinned Hawk
Zeiss Victory 32mm
Northern Cardinal
Swarovski 32mm
 
 

 

 

 


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