Binoculars

1. All binoculars are not created equal. There are brands and models available to suit any specific need you may have, and it pays to carefully research which is right for you.

2. Roof prism binoculars are streamlined and lighter than porro prism models. However, porro prism construction affords a clearer, crisper image.

3. A larger exit pupil allows more light into your binoculars, and is ideal for lowlight activities like bird-watching at dawn or stargazing. A smaller exit pupil is recommended for broad daylight viewing.

4. Compact binocular models, especially those with auto-focus, are ideal for kids. They are easy to use and carry, and sure to spark interest in the natural world.

5. Most lens glass is given a rating based on its quality. Look for lenses made with BaK-4 glass (barium crown), which is commonly used in high-end models.

6. Some binocular models are waterproof, fog-proof, and shock-proof, and feature rugged construction and tough, no-slip rubber shells. These are great in less-than-ideal weather conditions.

7. Image stabilization is offered on some high-end models and is ideal for use when viewing long distances or in unstable conditions. Microprocessors inside the body process image shake and adjust the angle of the glass to compensate, giving you a steady view.

8. "Field of view" refers to the amount of territory seen by looking through the lenses. It is determined by a combination of magnification and design of the lens and eyepiece. In general, more magnification means a smaller field of view, and an eyepiece with a wider angle will give you a greater field of view.

9. Astronomy binoculars feature very large objective lenses, some even up to 100 millimeters, for maximum light allowance, and magnification powers of 10x to 30x.