Shopping for binoculars Rancho Santa Margarita CA

Looking for a pair of binoculars can be tricky unless you know the numbers, said David Katz, owner of The Camera Company in Norwood.

Binoculars are typically described using numbers such as 7x35 or 8x42. Katz said the first number refers to the binoculars' magnification, or how much closer the binoculars make your target appear. The second, he said, refers to the diameter, as measured in millimeters, of the objective lens -- the one pointing away from your face that gathers light.

Determining which combination of magnification and objective lens diameter is right for you depends on where and when you are planning on using your binoculars, according to Ken Burg, assistant manager of Noble's Camera Shops' flagship store in Hingham.

Burg said those looking for binoculars they can use under conditions with less than ideal light -- for example in a forest or near dawn or dusk –- would do well to select a pair with a large difference between the first and second numbers.

The pupil shrinks and expands depending on the amount of light available. At its largest, when there is little light available, the pupil expands to a diameter of 7 to 8 millimeters -- so you should consider a pair of binoculars that can project a cone of light that has a similar diameter to your pupils to maximize the amount of light.

He said a good rule of thumb for determining the amount of light a pair of binoculars will project into your eye is to divide the objective lens diameter by the magnification.

''A small travel binoculars might be an 8x24, eight looks closer, but 24 is small,'' Burg said. ''If you divide eight into 24, it's three, the light is only about 3 millimeters, which can be great if it's the middle of the day and your pupils are closed a little.''

After you sort out the proper light ratio you need from your binoculars, you should consider what magnification is right for you. Katz said binoculars typically fall between the powers of 7 and 12.

For those interested in seeing long distances, zoom binoculars are available, the most common offering zooming to the power of 35, but Burg said zoom binoculars usually do so at the expense of some other feature, and can sometimes provide less than desirable results.

Prices on binoculars can range from $20 to more than $1,000, according to Katz and Burg. Most people pay from $150 to $500, they said.

''We don't carry any real cheap ones because they just fall apart,'' Katz said.


BINOCULAR SHOPPING TIPS

For bird watchers: The Audubon Society recommends using 7 or 8 power binoculars for bird watching. It warns against binoculars 10 power or stronger because they typically provide a smaller field of vision.

For boaters: Ken Burg, of Noble's Camera Shops, recommends using binoculars with powers not exceeding 8 or 10 because of the instability as the boat rocks in the water. However, image-stabilizer binoculars are available for those who wish to minimize the effects of rocking. Waterproof models are also available for those who are concerned about getting their binoculars wet.

Try them out first: Binoculars can be a subjective product. What works for one person may not for another. Local camera shop owners recommend trying a pair of binoculars before you buy them.

A.J. Bauer may be reached at ajbauer@ledger.com