8×42 binoculars are generally accepted to be the most versatile of all binoculars, since they are the ones you can use for virtually anything you might be interested looking at through your binoculars and in any circumstances – all-purpose, all-terrain binoculars. They are the best compromise between the very compact pocket binoculars and very big giant binoculars.
(The different price ranges which will form the basis for the reviewed binoculars will be found at the end of this post.)
8×42 Binoculars: Magnification: 8x:
The power available in ordinary binoculars vary from as low as 6x (some cases even 4x) to 12x; beyond that you move into the realm of giant binoculars. Magnification of 8.5 and 10.5 are also available. The 9x magnification always goes with giant binoculars.
Magnification of 6x is not powerful enough and 7x is better, but still marginally below par for an all-terrain pair of binoculars. On the other hand, higher magnification like 10x and 12x causes certain restrictions: You may see more detail with a more powerful binocular, but the first implication of more power is a less bright image. Furthermore, more power is also associated with movement sensitivity. The slightest movement, like “binoculars shakes” is amplified making finding an object (in particular when it’s moving) very tough. High magnification also causes a narrower field of view, which aggravates the problem of movement amplification. It also causes flatter depth of vision, which means that the focus will have to be adjusted more often. So observing birds up close is not easy at all with high magnification instruments. (For more information, go to “Binoculars explained , Magnification”).
The magnification which is a near-perfect compromise between the extremes, is 8x. You won’t have any problems getting a view of distant objects and to see enough detail at any range. However, 8x is not too powerful to cause problems finding objects due to things like narrow field of vision and “binocular shakes”.
8×42 binoculars: Objective lens/Aperture: 42 mm.: The 42 mm. diameter of the objective lenses is also a good compromise for a general purpose binocular. It’s not that big that weight and bulkiness become a problem, but big enough to gather a lot of light for excellent viewing throughout the day and even for reasonable viewing in less bright conditions.
Since their main specifications of all 8×42 binoculars are the same for all these binoculars irrespective of the price (magnification of 8x and aperture of 42 mm.), some of the other specifications will also be either exactly the same, or more or less the same.
Light gathering ability of all 8×42 binoculars is the same, since the apertures are the same: The Twilight factor (sq. root of aperture x magnification) is the same (18.33). The exit pupil (aperture/magnification: 42/8 = 5.25) is also the same in all the cases. This means that the Relative Brightness Index (RBI) (sq. of exit pupil) is also the same: 27.56. So, as far as these two important factors are concerned, the brightness of the image delivered to the viewer’s eyes should be the same irrespective of price of the instrument. However, in the end the quality of the optical glass and the optical coatings will make all the difference between the binoculars from the different price ranges as far as image quality is concerned.
In the world of binoculars quality always comes at a price – and that applies to 8×42 binoculars as well; making an excellent pair of binoculars is simply considerably more expensive than making one in the budget class – the price is not artificially inflated.
On the bright side many medium priced and even budget priced binoculars are acceptable to good. If you’re lucky, you could get an excellent pair of binoculars at an astonishing discount price.
Since so many features of all 8×42 binoculars are the same, the price tag will play a decisive role. Once that has been decided, some minor differences between the binoculars in the particular price range will eventually tip the scale in favor of a particular instrument.
Some fine binoculars have magnification of 8.5 and some objective lenses of 43 mm. – which are close to the 8×42. However, I stuck to the 8×42 binoculars to make comparison easier.
The following different 8×42 categories according to price have been distinguished: