Comparing Birding Binoculars
by Michael Porter
Buying a pair of binoculars is an important and expensive decision, and you want to get it right. After all, what other material possession will you depend on so often and carry so close to your heart?
Here are suggestions to help you choose the binocular that's right for you. The bottom line is that the best birding binocular is a custom fit. Often the most important factors are the personal ones, such as how a binocular fits your hands, how much power you can hand hold, and how much weight you can carry comfortably.
It became clear that we were looking at the resolution limit of our own eyes. This varies from individual to individual and does not improve with age. However, there were some young, teen-age eyes at the field tests, and though they could resolve smaller details, they got the same relative results when comparing two models as did their older comrades. The interesting conclusion is that the on-axis resolution of most decent binoculars exceeds the ability of most eyes to see it.
The resolution at the edges of the image, called off-axis resolution, was a different story. Here resolution differences were more apparent. This is where the top-end optics excel, and it's probably one of the main reasons people consistently preferred the most expensive binoculars.
Of course, resolution is only one factor that affects the perceived image quality. Brightness, contrast, color accuracy, the width of the field of view, how much of the image you can see with your glasses on all these elements affect the subjective experience. So many factors interact that truly objective comparisons may be impossible. This is why there is a continuing dialog among experienced birders about which binoculars are best. And it's why your personal experience looking though binoculars must be the ultimate test.
When you're ready to purchase, there is one important rule: try before you buy. The more time you spend handling and looking through the binoculars before you buy them, the likelier that you'll make a decision you'll be happy with.
If you can find a dealer who will let you return or exchange the binoculars, that's ideal. If a friend or someone in your local birding organization owns the model you are considering, talk to that person about the binoculars. He or she might even offer to let you try them out.
Here's a quick check for mis-alignment that you can do yourself. Look through the binoculars at a horizontal line, such as a telephone wire. Slowly move the binoculars away from your eyes until you see two images instead of one. The horizontal line should stay lined up. If the line appears higher in one circle than the other, the binoculars should be repaired.
The best binoculars
are constructed to survive heavy use. They can take a bump or two and
stay in alignment. It's a feature worth paying for.