Buying some long sight

Nandagopal Rajan        Print Edition: October 2012

We have all seen and used binoculars, but not many of us actually take the plunge and buy one. This is partly because we don't have a specific use for the product and find the need to have one only when we are on a vacation, that too on a scenic spot. But there are many people who are very serious about their binoculars, among them sports lovers, nature enthusiasts and bird watchers. These users are clear about the specifications they need while buying a device. But what about the average user? Here is a guide to selecting binoculars.

WHAT TO LOOK FOR

1. Magnification
The magnification of a binocular is the number that is written with the x. So if the binocular says 10x, it means it magnifies the subject ten times. For instance, a bird 1,000 metres away will appear as if it was at a distanc e100 metres away as see with the naked eyes. The best magnifications for regular use are between 7x and 12x, anything beyond and it will be tough to manage without a tripo

2. Objective Lens Diameter
The objective lens is the one opposite the eye piece. The size of this lens is crucial because it determines the amount of light that enters the binoculars. So for low light conditions, you get better images if you have a bigger diameter objective lens. The lens size in mm comes after the x. A ratio of 5 in relation to the magnification is ideal. Between an 8x25 and 8x40 lenses, the latter creates a brighter and better image with its bigger diameter.

3. Lens Quality, Coating
The lens coating is important because it reduces the amount of light reflected and allows the maximum amount of light to enter. The quality of the lens, meanwhile, ensures the image is aberration free and has better contrast. The best lenses work better in low light conditions as they transmit more light. They also ensure that the colours are not washed out or distorted. Users with spectacles should look for a high eyepoint.

4. Field of View/Exit Pupil
FoW refers to the diameter of the area seen through the glasses and is expressed in degrees. The larger the field of view the larger the area you can see. Exit pupil, meanwhile, is the image formed on the eyepiece for your pupil to see. Lens diameter divided by magnification gives you the exit pupil. An exit pupil of 7mm gives maximum light to the dilated eye and is ideal for use in twilight and dark conditions.

5. Weight & Eye Strain
One should consider the weight of a binocular before buying it. Consider if using the binoculars for a prolonged time tires you. Similarly, use a binocular and see if it is taxing on your eye. While it is difficult to use regular binoculars for more than a few minutes at a time, the high-end ones hardly cause any eye strain and can be used for long hours at a stretch if needed.

6. Waterproofing
Since binoculars are an essentially outdoor products, it is important that they have some degree of waterproofing-this is usually denoted as "WP". While regular models can stay under limited amounts of water for a few minutes, the high-end models are left undamaged even after a couple of hours submerged in water.

The best features for specific uses

1. Entry Level

binoculars


OLYMPUS 7X35 DPS I S
Rs 3,895
With 7x magnification, porro (double) prism and central focus this is a good option for the budget- conscious buyer.

CELESTRON UPCLOSE G2 10X50
Rs 3,591
This porro-prism binocular is also ideal for regular use and comes with 10x magnification and has a multi-coated lens.

NIKON SPRINT IV 10X21CF MB
Rs 4,450
This compact, lightweight model comes with multi-layer coated lens for a clear and bright image.

NIKON ACTION 7X35CF
Rs 4,950
Ideal for sports and regular use this model has 7x magnification and a 35mm objective diameter.

2.  MID-RANGE

binoculars


NIKON TRAVELITE VI 12X25CF
Rs 9,950
This compact device is ideal for travel and comes withamulti-layer coated lens and rubber armour coating.

BUSHNELL POWERVIEW 20X50
Rs 8,999
With porro prisms, this is good for birdwatching and nature watching. It comes with Instafocus adjustment and diopter controller and can be mounted on a tripod if needed.

CELESTRON SKYMASTER 25-125X80
Rs 11,635
This zoom model is ideal for astronomy thanks to the large aperture and multi-coated lens. Needs a tripod though.

3. HIGH END

binoculars


STEINER SKYHAWK PRO 10X42
Rs 42,426
This weatherproof model comes with a 42 mm aperture that delivers impressive luminosity even in low light helped by the special coating technology and high-contrast-optics. Ideal for birdwatchers.

CARL ZEISS CONQUEST 8X30
Rs 49,950
Despite being compact, this model offers a wide objective diameter and high-detail over long distances.

NIKON MONARCH 12X42DCF
Rs 26,950
Along with the wide objective diameter, this device has a dielectric, high-reflective, multi-layer prism coating for best light and is filled with nitrogen gas to make it fog-free.

SWAROVSKI HABICHT 10X40 W GA
745 pounds
Swarowski binoculars are at the very top due to their superior optics and exceptional build quality. This model promises extrawide field of view and bright, contrast-rich images.

A BINOCULAR FOR THE OCCASION

TRAVEL
Look for compact, lightweight models with mid-range magnification and field of view.

BIRD & NATURE WATCHING
Needs wide field of view and magnification of between 7x and 12x.

OUTDOORS
Look for rugged models with waterproofing, portability and durability. Ideal magnification is between 8x and 10x. Also look for large objective diameter and good lens coating so that it works well in rising and setting sun conditions.

MARINE

Look for waterproofing with a wide field of view and vibration reduction if possible.

ASTRONOMY
Aberration corrected binoculars with large objective diameter and exit pupil are best.

THEATRE/MUSEUM

Compact models with magnification of 4x to 10x can be effective while watching stage performances. In museums, lightweight models with low magnification and focusing distance of less than two metres are recommended.

SPORTS
Look for wide field of view and 7x to 10x magnification. Zoom functionality can be an added advantage.

TRAVEL
Look for compact, lightweight models with mid-range magnification and field of view.

BIRD & NATURE WATCHING
Needs wide field of view and magnification of between 7x and 12x.

OUTDOORS
Look for rugged models with waterproofing, portability and durability. Ideal magnification is between 8x and 10x. Also look for large objective diameter and good lens coating so that it works well in rising and setting sun conditions.

MARINE

Look for waterproofing with a wide field of view and vibration reduction if possible.

ASTRONOMY
Aberration corrected binoculars with large objective diameter and exit pupil are best.

THEATRE/MUSEUM

Compact models with magnification of 4x to 10x can be effective while watching stage performances. In museums, lightweight models with low magnification and focusing distance of less than two metres are recommended.

SPORTS

Look for wide field of view and 7x to 10x magnification. Zoom functionality can be an added advantage.


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