Compact and fully multi-coated, the Opticron Natura BGA Roof Prism binoculars are aimed at the enthusiast wanting a lightweight, yet robust and reliable pair of binoculars for general observation. The Natura BGA 8x42 Roof Prism binoculars offer a long eye relief, are nitrogen filled, waterproof up to 3m and are wrapped in a durable, textured rubber armouring for a comfortable grip. Featuring a ... More
Opticron Natura BGA 8x42 Roof Prism Binoculars
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Compact and fully multi-coated, the Opticron Natura BGA Roof Prism binoculars are aimed at the enthusiast wanting a lightweight, yet robust and reliable pair of binoculars for general observation. The Natura BGA 8x42 Roof Prism binoculars offer a long eye relief, are nitrogen filled, waterproof up to 3m and are wrapped in a durable, textured rubber armouring for a comfortable grip. Featuring a tried and tested optical system packaged in a brand new double hinge body, the Opticron Natura BGA delivers an unbeatable combination of user comfort, performance and value.
The Key Features
8x magnification - suitable for general observation
42mm diameter objective lenses
Compact fully multi-coated optical system with high quality 'PC' phase corrected prism units and Oasis prism coating
High resolution optics with excellent colour correction
Perfect 50:50 balance in the hand
Long eyerelief eyepieces giving full field of view for glasses wearers
Nitrogen waterproof to a depth of 3 metres
Durable textured natural rubber armouring delivering comfort and grip
Wide wheel glide-action focusing with locking central dioptre adjuster
Infinity focus to 3m in under half a turn
Multi-stage rotating eyecups in hard-wearing alloy (4-stage 8x42, 3-stage 10x42)
Threaded socket for connection to a binocular tripod mount
The Opticron Binocular Guide
B when seen on roof prism binoculars including Opticron BGA = full field of view for spectacle wearers
GA = rubber armouring
W or WA = wide angle vision
E.g. 8x42. The number ‘8’ denotes the magnification and means an object appears to be 1/8th of its actual distance away. Using this rule an object 40m distant appears to be only 5m away. ‘42’ is the diameter of the objective lens (the large end) in mm through which light enters the binocular.
Within any given range of binoculars the higher the magnification relative to the objective lens diameter, the lower the apparent image quality. Images appear less sharp and have a lower ‘relative’ brightness and poorer colour contrast. Higher magnification binoculars also;
a. have a shallower depth of focus (distance in focus at any one focus setting), requiring more use of the focus wheel.
b. amplify natural hand-shake affecting the stability of the image being viewed.
For general observation choose a 7x or 8x magnification. If you want binoculars of 10x or over try them first.
What objective lens size?
The amount of light entering a binocular is directly related to the surface area of the objective lens (OG). A 50mm OG will admit 2.5x the light of a 30mm OG. The amount of light reaching the eye is known as the exit pupil diameter (EPD) and its size can be found by dividing the OG diameter by the magnification. For example the EPD of an 8x32 = 4mm while the EPD of an 8x56 = 7mm. As a general rule the iris dilates between 2 and 3 mm (bright sunlight) and 6 and 7 mm (twilight) and so a choice should be made on the type of use the binocular is being put to. For general use choose a 7x42 or 8x42 binocular with an EPD of +5mm.
The field of view of a binocular is dependent on the optical design and not simply a product of the magnification and objective lens diameter. It is expressed as either the width of panoramic view in metres from a distance of 1000 metres or in degrees where 1° is approximately 17.45m.
Many binoculars provide the full field of view when wearing glasses by either folding down the rubber eyecups or by turning/pushing retractable eyecup assemblies to the ‘down’ position. As a general rule the longer the eyerelief - the distance between the surface of the eyepiece and the point where the pupil is positioned for full field of view - the better the instrument for spectacle wearers. If you think you want to wear glasses while using your binocular, choose one with an eyerelief of 15mm or over.