If you are like me, you’ve probably owned many different pairs of binoculars in your life. I’ve had many good sets, decent sets, and bad sets. As a passionate bird watcher, it’s important for me to have binoculars that feel very light, focus quickly, and still work in dim light conditions. As anyone who uses binoculars knows, it’s vital that you get a pair of binoculars that are sealed against environmental problems. Environmental factors like rain, moisture, salt can all cause problems with your binoculars. Now before you pick your binoculars, there are a few key things to look for.
First, the design is something you should know about. Binoculars all work the same. Light enters the lends, gets magnified then flipped, and enters your eyes. Binoculars all focus by moving lenses. Now there are two main differences in the flipping design. It’s necessary that the flipping happen because otherwise the image would be upside down – no good. Both designs utilize a prism to ensure the flipping, but it’s the placement of these prisms that effect the design of the lens.
A basic prism is used in one design to flip the image. This basic design has remained unchanged until the mid 1900’s when the roof prism design was developed. The roof prism design is a lot more complex than the basic prism design and has more light loss through the reflections. Advances in optic coating have allowed the loss of light to be greatly diminished. This design is more expensive, however. Either design is effective, however.
Binoculars come with two numbers – 10X50 Binoculars, for example. These will indicate both the power and the diameter of the binoculars. Now, you might thing that the larger the first number, the better the binoculars, but this is not always the case. You have to take into account how much magnification you can hold while keeping the binoculars steady. There’s no point having a super powerful magnification when you can barely see the bird because of the handshake effect. For most people, 10X magnification is about all you can handle. Second, any sort of high power magnification does little good when looking at small birds (or other objects) because of the very narrow field of view.
The diameter of the lens will affect, in part, how much light is let in. Diameter is not just the only thing that effects the light, the type of coatings on t he lends will too. Coating the binocular lens with magnesium fluoride will allow more light to pass through the lens too.
So 10×50 binoculars have a 10 X magnification and a 50mm diameter – one of the best bird watching tools out there.