Have a look at our binocular buying tips before you head down to the local marine supply store. This article aims to provide basic information about marine binoculars provided by our experts, which will help you make an educated choice on your next purchase.
Boaters need and use binoculars for many reasons, the most important of which involves the safe operation of your boat. Mariners should use them to read and confirm the numbers on a navigation marker when needed or to identify navigation lights on a ship or boat at night. Fishermen use binoculars to scan the horizon for breaking fish or birds diving on bait pushed upby predators lurking below.
First, let’s talk price, what is out there and how much will it cost you. Marine binoculars range in price from about $100 to over $1000, depending on features, construction quality, lens materials, and water-resistance capabilities.
Lens Size and Magnification
There are two numbers that help identify a couple of important binocular characteristics. The first number is the magnification factor provided by the binocular. The second is the measurement in millimeters of the objective lens, the large opening at the front. The most popular marine binoculars will be rated 7 x 50, this means the magnification is seven times what you would see with the naked eye and the objective or front lens is 50 millimeters in diameter.
The higher the magnification power of binoculars, the more difficult it is to continue to get a good clear image. Odd, but true. A magnification of seven times should be more than adequate for most situations and is considered the maximum magnification useable on a small boat.
Binocular Buying Tips—Waterproof Rating
Next up is waterproof construction. Binoculars that are not waterproof will trap moisture, and the lens may become fogged, which would impede your view. Obviously this is not what you want in a quality marine binocular. Waterproof construction is a must. Most marine binoculars are indeed waterproof, but double-check the specifications to be safe. The best binocular will have the lens cavities filled with an inert gas like nitrogen as an aid to prevent water intrusion.
Also consider buying a binocular float strap, which will prevent the binocular from sinking if they fall overboard. These straps are usually a bright color to make it easier to find your wet binoculars. Top brands supply these as standard equipment.
Eye Relief—More is Better
This one is very important if you wear eyeglasses: Eye relief, measured in millimeters, is the maximum distance your eye can be from the eyepiece and still see the full field of view. Most marine binoculars have an eye relief from about 18 to 27 millimeters. A higher number is better for eyeglass wearers.
Focus and Light
The amount of light a particular binocular will allow through the lens makes a difference in the quality of the image you will be viewing. Lower-priced models will let in about 75 percent of the light to pass to your eyes, while that percentage is more than 90 with higher-quality models.
Field of view is the width of the image you see at a distance of 1,000 yards. A marine binocular with a field of view specification of, let’s say, 300 feet will allow you to see an image that is 300 feet wide at a range of 1,000 yards. Most 7 x 50 marine binoculars will have a field of view between 350 and 400 feet at a range of 1000 yards.
Ease of focusing must be considered before purchasing a set of marine binos. With some binoculars, each lens is focused individually. This can be very good if your vision quality in one eye is significantly different than the other. Center-focus binoculars use a single control to the adjust sharpness of the overall image.
Binocular Buying Tips—Compass and Range
Check to see if your marine binocular of choice has a bearing compass. Having one means there will be a superimposed image of a compass bearing in the image that you see. A bearing compass is a useful navigational aid for the boater and fisherman.
An internal rangefinder reticle gives you the ability to calculate your distance from an object. You need to know the height of an object, and then measure the angle to its top using the rangefinder reticle. Remember that navigation charts often include heights of navigation markers that can be used as your reference height.
This wouldn’t be much of a binocular buying tips article if it failed to talk about marine binocular weight. A heavy binocular would be considered to be over two pounds in weight. Some mariners find heavy binos to be easier to hold steady and better for viewing objects on a rocking boat.
Warranty. Most top notch marine binoculars are backed with at least a 25-year warranty. Some even have limited lifetime warranties.