Marine binoculars play a vital role at sea. They can allow tourists and pleasure cruisers to spot whales, sharks and other sea animals at massive distances, while for crew they provide an invaluable resource for checking the weather, spotting threats to the ship or boat, and identifying approaching vessels.
Made from two identical, mirror-symmetrical telescopes placed side-by-side and aligned together, binoculars grant hunters an incredible depth of field and magnification while retaining the eye’s ability to see objects in three dimensions, something which a monocular telescope is unable to do.
When considering marine binoculars, the three most important things to think about are the construction and the magnification. Marine binoculars should be sturdy and robust – for complete waterproofing, nothing does the job better than a pair filled with nitrogen. However, these binoculars can run over the $200 mark for a very basic pair. Any binoculars taken out on a boat should have some degree of waterproofing, hence why many birdwatching binoculars are unsuitable for use in a maritime environment.
Magnification and zoom require a bit more thought and consideration. The theory behind this conundrum is simple - the higher the magnification of the binoculars, the further the distance visible. However, as you zoom progressively closer, the field of view becomes more restricted, and the image may not be quite as clear as a lower magnification could provide.
However, in a marine environment there is a second consideration to take in to account. The natural motion of the boat can make it exceedingly difficult to track and locate efficiently at higher magnifications. As a result of this, most marine binocular users plump for a maximum of 7x resolution. This is normally combined with a maximum objective lens of 50mm, ranging down to 26mm for smaller binoculars. However, the 7x50 is considered by most users to be perfect for use on deck.
In addition to these differences, many marine binoculars come with a built-in compass, making them ideal for locating landmarks or buoys from a distance, and then taking an immediate bearing. From a nautical viewpoint, this combination of two of the maritime trades’ most useful tools is an absolute godsend. Early models (developed during World War II) were not always successful as some of the compasses were not manufactured to a high standard, or because parts of the binocular influenced the magnetic field of the compass, but over the last two decades there have been vast improvements in the quality of the compasses incorporated into marine binoculars.
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