CPBN29 7x28 Apache Military Binoculars with Reticle Item No. CPBN29 List Price: $375.00 Online Price: $337.50	CP637 7x50 Center Focus Binoculars Item No. CP637 List Price: $145.00 Online Price: $130.50	CP647C 7x50 IF Binoculars w/Compass Item No. CP647C List Price: $289.00 Online Price: $260.10
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CPBN1A2 7x50 Navy One Binocular Item No. CPBN1A2 List Price: $425.00 Online Price: $382.50		CP657 Sentinel Binocular Case Item No. CP657 List Price: $48.50 Online Price: $43.65
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A GUIDE TO CHOOSING YOUR BINOCULARS "How much power and power defined" Prismatic binoculars are referred to as 6x,15; 7x,35; 8x,30; etc. The 6x, 7x, 8x, etc., refers to the power of the glass; namely to the extent it magnifies of 8x makes an object being viewed. Thus a glass of 8x makes an object look eight time larger than it does to the naked eyes and consequently makes it appear refers to the diameter of the objective lens in millimeters. The objective lens is the large lens far farthest from the eyes; the ocular lens is the small lens which is closest to the eyes when the binoculars are in use. Too many binoculars users select their glass solely on the basic of power, believing that the highest of power the better most be the binoculars. This is better must be carefully chosen to private exactly the right power for your special use or uses, neither too much nor too little. Remember, the higher to the power the smaller the field of view and the lower brilliance of the image that reaches the eyes. The clarity and definition also decrease as the power increases and, most important, not only does a binocular magnify the object being viewed but also any motion of the hand holding it and the motion of the object you are in or on such as the floor of a car, the deck of the boat, etc. It is generally recognized, therefore, that above 8x, a glass should be used in conjunction with a rest or tripod to obtain best results. The higher power glasses (10xand above) uses such as long range game stalking, mountain scenery, etc. This is why you will find binoculars of 6x, 7x and 8x recommended for nine of the ten user. "Relative Brightness and Exit Pupil..." Relative Brightness and Exit Pupil are determined mathematically. The exit pupil of a binocular is the disc of light one sees in the eyepiece when holding a binocular at arms length towards a bright light. To compute Exit Pupil: divide the diameter of the objective lens in millimeters by the power of the binocular. To compute relative Brightness: square the Exit Pupil. Example 7x35, means the prism binocular described magnifies seven times and has an objective lens of 35 millimeters. Exit Pupil equals 5 and 5 squared equals a relative brightness of 25. Relative light Efficiency is the modern term used to describe the increased light transmission that coated optics give. R.L.E. is computed by increasing Relative Brightness 50%. The Relative Brightness figure of 25% given above would equal a Relative Light Efficiency of 37.5. Barium Crown prisms further increase R.L.E. by from 10-15%. Never types of coating including multi-coating, also increase the R.L.E. factor. "Field of View..." Field of view refers to the diameter of the area seen through the glasses. As wide a field of view as possible is most desirable under all conditions and Swift binoculars are especially selected to private the maximum filed of the view consistent with other necessary factors. It should be noted again that smaller must be the field of view and vice versa. Filed of view is often expressed as an angle. Swift retractable eyecups allow eyeglass wearers a full filed of view. "Central vs. Individual Focusing..." Central Focusing binoculars are focused by a single knurled wheel. An adjustable right eyepiece is provided for any difference between the eyes. Because they are convenient to use, central Focusing binoculars are in the greatest demand today. Individual Focusing binoculars are adjusted for each eye at the eyepiece. Because they are more nearly moisture proof, simple, and sturdy in construction, military services require individual focusing on binoculars they procure. Mariners and sportsmen, who are the sole user of a binocular, focus each eyepiece on infinity and either note the setting on an eyepiece for later use or tape eyepieces in position.

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