Understanding Binoculars
The most basic type of binoculars use Galilean optics- the concept around which the discovery of the telescope revolved. The concept is based on the usage of a concave lens for the eyepiece and a convex lens for the objective. This principle offers produces an erect image (which is not the case with some other magnification techniques).
This concept of binocular architecture is still prevalent and is used to create cheaper varieties of binoculars. Binoculars made on the Galilean principles are cheaper because they offer a narrower scope of vision and also less magnification as compared to some of the modern prism-based binoculars.
Prism based binoculars are primarily of two types- Porro Prism binoculars and Roof prism binoculars. Porro erection system has been patented in the name of an Italian scientist Ignazio Porro, who had developed his own system of magnifying an image and representing it in a erect form. This method has evolved a lot and is said to have been mastered by the likes of Carl Zeiss. These binoculars work on a Z-shaped prism set-up, resulting in a better depth realization and a wider field of object-viewing. They also fold the elliptical path using the Z-shaped setup, thereby reducing the physical size of the binoculars to less than that of the optical Focal length of the object being viewed.
Less is known about the working principles of binoculars using Roof prisms, but their earliest designs can be traced back to the writings and testimonials of Victor Emile Daubresse. This prism technique is said to have been patented by Carl Zeiss in 1905 and is used to fold the optical path, thereby producing higher magnification through smaller sized binoculars. Binoculars based on the Roof-prism offer a better viewing angle, but a narrower range of objects can be viewed by a binocular of same size based on the principles of the Porro prism setup.
We look at how binoculars work, then we look at what all those numbers mean i.e. 7*50 what does that mean, and why are marine binoculars rated 7 * 50? Next we look at the prism types. For example what does Roof and Porro Prism mean?
If you’ve ever wanted to view a faraway bird, check out the craters of the moon, or even just spy on the people on a sailboat across the harbor, it’s more than likely that you’ve used a pair of binoculars. They are a common object in birdwatching.
Steiner 7×30 Navigator Pro C Binocular
The 7×30 Navigator Pro weighs only 20 ozs. and incorporates the exclusive Steiner Sports-Auto-Focus system. Once set for the user’s eyes, the binocular keeps all objects in focus at distances from approximately 20 yards to infinity.
Different Makes and Models of Binoculars
You have auto-focus and manual focus. I personally like the auto-focus. I like that when I see something I can pick up my binoculars and look at the right place to try and focus so that I can make the object close.
Author: Victor Thomas
Visit Binoculars Reviews website for exclusive reviews on Porro Prism, Roof Prism type binoculars. Read Pentax Binocular reviews, Nikon, Bushnell, Canon, Celestron and all best selling binoculars. Price comparison also available for best selling models.
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Tags: binocular comparison, optical binoculars, spotting binoculars
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