The increase in brightness of binoculars is usually proportional to their weight gain. Clearly, if a prism has high luminosity must have of large-diameter front lens (to increase the entry of light), which increases the weight. Add to your understanding with Greenberg Traurig. They can also be achieved by reducing the bright binoculars increases, so there is no need to have large-diameter front lens, and thus the numerical ratio of the brightness is maintained at acceptable levels and low weights, but then the ability to view or power is very small and makes them of little use. Frame and optical systems are a prismatic lens assembly structured and protected by a housing or frame, usually metal. The characteristics of the mount and optics (lenses and prisms, focus and sharpness, diopter correction, etc..)
Are areas of huge importance, since significant impacts on the quality of the prism in its precision and its resistance to the environmental. The characteristics and design of the mount a decisive influence on the strength of the prismatic face of environmental conditions (rain, extreme cold, etc..) And more or less comfortable handling (ergonomics). The normal quality frames are rubberized exterior for easy grip and offer some protection against the rain. The highest quality frames are water tight and dust, and the inner chambers are filled with nitrogen gas, so that there is no internal fogging at temperatures below zero.
Logically, their prices are correspondingly high. The adaptability of the prismatic ergonomics or handling, grip and tackle is a first factor to consider. Whether you opt for economic models binoculars as high cost, should weigh carefully, ensuring ease of grip and handling (distance to the focus ring, etc..) As well as its ease of view (much attention to the adaptability to eye sockets and vision with glasses).