Magnification and objective lens diameter
A set of two numbers is used to specify most binoculars. The first can tell you the magnification power while the second is an indication of the objective lens diameter. Why do these two matter?
On the one hand, the magnification can let you know how close your subjects will appear. Most people tend to think that bigger is better, which is to say that they might pick a pair of binoculars with a superior magnification only because they believe it’s a good thing. The fact is that, with a higher magnification, you’ll find it difficult to stabilize the image. Everyone’s hands are shaky, and you might end up having to use a tripod.
The bigger the objective lens, the brighter will the image be. However, it’s pretty obvious that a larger lens will make it harder for you to carry the binoculars as they will be heavier than a regular compact alternative.
Who will be the person using the binoculars?
There are many units available for sale out there, but something that matters quite a bit is the user and not just the specs of the unit you’re thinking of purchasing. The age of the person using the product matters because children have close-set eyes so you need to know that you can adjust the interpupillary distance.
If the individual wears glasses on a regular basis, you need to make sure that the eye relief is on par. If poor vision is an issue that needs to be addressed, the user obviously requires a bigger lens so that the binoculars are capable of gathering more light.
Prism
Most of the models that come with a roof prism system boast objective lenses that line up directly with the eyepiece. What this means is that the product will have a slimmer design and will prove to be a portable friend in need. Porro prism binoculars do not have their eyepiece all lined up with the front lens. However, they do offer a somewhat wider field of view compared to their roof prism counterparts, and a generally better depth perception.
