What Do We Mean By Birding Binoculars?

When Optics workers are asked to recommend the best binoculars binoculars they are very careful to say it depends on what they are going to be used for.  It also matters what the needs the individual user has.  Let’s take a closer look at these.

What kind of capabilities are important? The birder needs to see the patterns and color of feathers, often in suboptimal light conditions like a tree canopy or twilight. They need the ability to make an identification at a long distance and be able to focus cleary at extremely short ones.

They need true color viewing so everything appears the same as to the naked eye without unnatural tinting or color correction. The field of view should be wide so they can observe birds in flight and pick birds out from the surrounding trees.

Binoculars must be light to carry and use with a neck strap. They should be light enough to grasp comfortably and the view should be easy on the eyes for long periods. Birders usually want them compact enough to for a rucksack. They should have an adapter for a mono or tripod.  Rugged construction with some degree of waterproofing and fog-proofing is also preferable for wilderness viewing.

Magnification And Objective Lens Diameter

Two numbers define the basic specifications for binoculars. The first number is the magnification factor.  For instance an 8x binocular magnifies an image 8 times. High magnification makes it difficult to keep the bird in view and also the field of view will be smaller. For birding, an 8x binocular is the most commonly used magnification.

The second number gives the diameter of the objective lens.  The larger the diameter is the more light is captured by the binocular.  This makes the resulting image clearer and brighter.  The larger diameter also makes a larger field of view. In the birding world, the most popular objectives are 40mm and 42mm. Going much higher makes the binocular a little too heavy and cumbersome.

Lens And Prism Quality

Lens and prism quality and the optical coatings are also important.  Coatings reduce loss of light through reflection and help to preserve clarity and true color throughput. Fully-Multi-Coated (FMC) coatings are best for bird watching. Eye relief refers to the distance from the eyepiece to the eye. Those who wear glasses need more eye relief for the extra distance between the binocular and their eye caused by their glasses.

Roof and Porro Prism designs are the two body styles of binoculars.  Roof prism types are more compact and modern looking. Their objective lenses are more in line with the eyepieces, but porro prism types are more the traditional style with lenses stepped out from the line of the eyepieces. Birding enthusiasts are now choosing the roof prism type because the quality has caught up with porro types in recent years.