Choosing Binoculars for Nature Study

my binoculars

For the naturalist, binoculars are the most essential equipment besides keeping a nature journal.

I use them in my backyard to get a good look at birds at my feeders. I have found them useful in watching butterflies, just ten feet away.

With a good pair of binoculars with close focusing, you can watch:

  • birds
  • butterflies
  • dragonflies
  • spiders
  • large mammals
  • small mammals
  • dangerous animals
  • leaves on tall trees
  • flowers in inaccessible places
  • objects not easily seen from marked trails
  • and birds of prey flying high overhead

Features and what they mean

Viewing power is stated by magnification times objective size.

An example is 8X42. This translates to 8 times magnification and a 42 millimeter diameter objective lens. The image is magnified 8 times the size seen by the naked eye. A bird that is eighty feet away seems just 10 feet away.

The objective is the large front end. The larger the glass end, the more light is let in and the brighter and sharper the image will appear. This is important in low light situations such as in woodlands or at dusk.

Features to choose for nature watching

Close Focus is the ability to focus and clearly see an image a short distance away. For watching warblers or butterflies, most people choose close focusing of 6 feet or less. If this is you main type of viewing, try a model with as short a close focus as possible.

Field of View is how wide a scene of landscape you see through the lens. The higher the magnification power, the narrower the field of view. Large objectives do not increase the field of view. In other words a pair of 7X35 will have a wider field of view than a pair of 7x50s. This is due to eyepiece design. The wider the field of view the better the chance of keeping a moving bird in your sights.

Most models that are rubber coated are water-resistant. If your binoculars may possibly be submerged, like during hiking and canoeing, look for waterproof models.

Points for Eyeglass Wearers

Most models come with adjustable eye pieces for eyeglass wearers. These are eye cups that roll or fold down. These cups work best with moderate near-sighted or far-sightedness. I have monocular vision; one eye is far-sighted and one eye is near-sighted. Each of my binocular eye cups adjusts just fine to my eyesight and I don’t have to wear glasses with them.

If you have moderate to severe astigmatism you will probably need to wear your eyeglasses. Trying a pair out is key to comfortable viewing.

Compact Models have:

  • the same magnification strengths such 7 or 8 times
  • smaller objective lenses such as 21 or 25 instead of 35 or 42
  • come in sizes – 7X21, 8X25, 10X25

This is “you-can-carry-them-in your-pocket” size. I have a pair and really like their small size. The limitations aren’t many. The smaller objective may deliver an image not as bright, but in bright daylight that may not matter. Also the field of view may be narrower.

The small size may sound great if you have weakened arm strength but a compact’s small size is affected by hand tremors. Larger models can absorb the tremors and give a steadier image. And your arms are heavier that your binoculars. It is most likely holding up your arms is what makes your hands shake.

This size is good for their portable size and backyard viewing.

Full-sized Models Have:

  • have magnification strengths such as 7 or 8 times
  • objective sizes such as 35 to 50 mm in diameter
  • comes in sizes such as 7X35, 8X35 or 7X42

Full-size models can are very versatile. These models can offer the widest range of viewing in different situations. My Pentax 8X43s have served me well observing migrating birds of prey on Hawk Mountain and migrating spring warblers in nearby woodlands.

Large-size High Powered Models Have:

  • 10x power or higher magnification
  • objective sizes are 35 to 50 mm diameter
  • come in sizes such as 10X30, 10X42, 12X50

The bigger “binocs”, the heavier they are. These heavier models may need extra support such as a tripod or wide neck strap. The 10x magnification is probably the largest a person can hold without tripod support. The extra magnification revels more details and can see longer distances. These are good for watching raptors, waterfowl and large animals.

Choosing a Good Pair

I can almost guarantee that one year after you buy your binoculars new models with fancier features will come on the market. I learned the hard way after buying an expensive pair of binoculars. It was before close focusing was perfected. I can’t use these expensive, heavy gems to watch butterflies and dragonflies several feet away. But, they are still exceptionally good for watching birds at a distance.

My last pair is an excellent moderate-priced of binoculars. I choose Pentax 8X43s and I am very pleased with them.

There are no “perfect” binoculars. Choose a model within your budget. Set your priorities. Choose your two most frequent viewing situations and buy for them,  you may not do every type of viewing.

Birding magazines often test models and print articles a couple times a year. Look in Birder’sWorld, Wild Bird and Bird Watcher’s Digest. Consumer Reports publishes product reviews. Optical suppliers also have online articles on the ins and outs of choosing suitable binoculars. Christophers Ltd. has several pages on choosing binoculars.

After using the articles to narrow down the choices, a trip to a sporting goods or birding store will allow you to “test drive” a model before buying, even if you buy them online.

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