Choosing the Right Binoculars

Choosing the right binoculars can seem like an overwhelming task. Unless you are familiar with binoculars the strange terms can be confusing and lead to a frustrating experience. Choosing the right binoculars does not have to be a matter of luck. This article will help you select the right binoculars for your needs. The way you plan to use your binoculars will dictate which binoculars you should choose. Important quality considerations should include waterproof and shockproof ratings, magnification, objective lens diameter and lens quality.

Binoculars are simply two parallel scopes made up of an objective lens (closest to the object being viewed) and an ocular lens or eyepiece (closes to the viewers eys). Prisms are mounted between the lenses to compensate for the objective lens flipping the image over.

New models of binoculars often feature a roof prism rather than the Porro prism commonly found in older models of binoculars. Binoculars with roof prisms have a more streamlined look than traditional binoculars.

Binoculars are categorized by their magnification and objective lens size. For instance, binoculars may be referred to as 8x25 or 10x32. The first number refers to the magnification of the binoculars. The magnification indicates how many times larger the image will appear than if you were looking at it without binoculars. The greater the magnification the greater the detail but it is also harder to hold still than lower powered binoculars.

The second number refers to the diameter of the objective lens as measured in millimeters. The larger the objective lens the more light can enter the binoculars. Greater than 10x magnification usually requires a tripod to use effectively due to natural, slight hand shake. Magnification above 10x can also result in image distortion in very hot weather due to heat shimmer. The greater magnification can also decrease the depth of view causing the image to appear flat and shallow. Full-size binoculars (greater than 42mm) offer greater low-light viewing but are also heavier and larger. Compact binoculars (25mm) offer less low-light functionality but are smaller and lighter.

The field of view is the widest dimension seen through the binoculars. The greater the magnification the smaller the field of view. Binoculars with a wider field of view are helpful for watching active wildlife and sporting events where the subject is continually moving. The field of view is either listed as a number of feet at 1,000 yards or in degrees (one degree equals 52.5 feet per 1,000 yards). It is commonly thought that the objective lens determines the field of view; generally this is more due to optical design than objective lens size.

Lens quality is an important factor in how well binoculars perform. Glass lenses are heavier but provide better quality than the lighter plastic lenses. Plastic lenses that are of comparable quality to glass lenses are more expensive than the glass equivalent. The better the glass quality the better the image. High quality lenses may be described as Extra Low Dispersion (ED) or High Definition (HD). Lens coatings are applied to reduce light reflecting back off the lenses. Several coating options are available. If you are planning to use your binoculars in low-light conditions then better lenses will be a very important factor in choosing your binoculars.

The exit pupil refers to the amount of light sent to the eye. The exit pupil can be calculated by dividing the magnification power by the objective lens size. A larger exit pupil will let more light through to the eye resulting in a brighter image; however, lens quality and lens coatings are also a factor in determining how much light is actually sent through to the eye. Light transmission or transmittance is a term that refers to the percentage of available light that passes through the binoculars to the eye.

The eye relief refers to the distance from the eye to the lens before the field of view becomes limited. Eye relief may vary from 5mm to 23mm. This is a particularly important consideration for eyeglass wearers. Eyeglass wearers will find that to use binoculars with short eye relief they will need to remove their eyeglasses. Choosing binoculars with long eye relief will allow eyeglass wearers to use their binoculars with their eyeglasses on.

Adjustable eye cups allow the user to adjust how close the eyepiece of the binoculars is to their eye. Some eye cups are soft rubber and fold down while other are adjustable by turning the eye cup piece. Adjustable eye cups allow the user to position the binoculars comfortably and to block light entering from the side.

Binoculars have adjustable focus. The most common adjustment is a center focus adjustment which has a central focus mechanism to adjust both sides at once. Some binoculars have individual focus where each eyepiece may be focused individually. Some binoculars also have a diopter adjuster allowing one eyepiece to be adjusted to compensate for differences between eyes.

Many of the better binoculars are also waterproof. Waterproof binoculars not only keep water out when it is raining but are less likely to fog with climate changes (like getting out of an air-conditioned car on a hot day). One method used to waterproof binoculars is nitrogen purging. Nitrogen purged binoculars have the air inside the binoculars replaced with nitrogen to prevent moisture and moisture-related problems.

There are many considerations when choosing binoculars. Binoculars brightness and image quality is affected by several factors, including objective lens size, prism quality, lens quality and the quality of the lens coatings. A commonly accepted guideline is to buy the most expensive binoculars you can afford. Probably the best place to begin is to decide how you plan to use your new binoculars and then decide what is best for you. There is no single correct choice. The correct choice will vary depending on how you plan to use the binoculars and how much you can afford to spend.