In this guide we hope to give you the knowledge base you need to select the perfect optic for your application as well as giving you an understanding of how each item in our specifications list affects the optic you are looking to purchase. We will be adding to this guide continually, so check back often for updates and additional information.
The diagram to the right (or below on mobile) shows the core parts you will find on most binoculars - use this as a reference when we are describing different parts of the binocular. At its most basic level the objective lens gathers light while inverting the image, that light goes next into the prisms which correct the inverted image (rotate and flip it back to the correct orientation), which then goes into the ocular lens which magnifies the original image. The focus wheel moves a lens in the housing to bring the image into focus while the diopter adjusts for differences between the left and right eye. Most of our optics come with strap attachments, and a method to attach to an adapter.
Magnification will be one of your first considerations when it comes to selecting an optic. Are you (relatively) near or far away from the object you want to view? Is the subject you are viewing moving?
In the case of wildlife viewing magnification is very important. If you are cataloging the birds in your backyard for instance you will be relatively close to your subject and (being a bird) it is likely to move about quickly. For this application you would want a low magnification - this will increase your field of view and make it easier to find your subject - and see identifying characteristics. If you look at the diagram below you may be looking at a pronghorn, because both sexes can have horns one needs to find a dark cheek patch to signal the animal is male. For this application you may want a mid to high magnification for making that determination.
FIELD OF VIEW
Field of view (FOV) shows up a lot in our specs as well as in articles about what optics to buy, but what does it mean? Simply it is just the amount of space you can see through the optics measured in degrees.
You can see in the diagram to the left the higher the magnification the smaller the field of view. It seems important to note that the largest drop in field of view is between the 9x and 11x (or 8x and 10x in other models). Optics with a wide field of view equate to being better able to find your subject, following moving targets, and are less likely to magnify shaking from the user.
According to Wikipedia a typical human visual field is over 200° with both eyes (though much of it is peripheral). These B.2's are rated at 7.4° (7x). All are measured at 1000yds. At 1000yds every degree of view is equal to 52.5 feet. So If you take the amount of degrees and multiply by 52.5 you end up with the horizontal distance you can see in your optic. The last spec that you’ll see FOV in is Apparent FOV; this is the FOV in degrees multiplied by the power. In our example to the left the 7x comes out to 51.8°. This number describes your field of view through the optic.
Wikipedia contributors, "Visual field," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Visual_field&oldid=993364595 (accessed December 14, 2020).