Bushnell Powerview 10x42
Bushnell Powerview 10x42 is part of the Powerview series which is the entry level series from Bushnell; the viewers come in a variety of magnifications and have a sharp price/quality ratio. The coatings of the glass are, depending on the type, multi-coated or fully multi-coated. The lens coatings are designed to guide the light captured by the lens to the eye in the most efficient way. On the outside, almost all models have an extra rubber grip layer so you have (and keep) everything completely under control! In the middle is a convenient and easy to handle focus knob to get the sharpest view of your target. The Bushnell Powerview 10x42 compact is provided with fold-down eyecups so you can use the viewer in no time even when wearing glasses.
For travellers, nature lovers and concert-goers among you
The Bushnell Powerview series are entry binoculars suitable for many purposes. They are all equipped with an anti-slip casing so that the binoculars will not fall out of the hands. You can choose between binoculars with a multi-coating and fully multi-coated binoculars (higher light output). Binoculars with a higher magnification are also equipped with a tripod connection (see specifications).
The Powerview series is available in a wide range of magnifications; if an object is farther away it is wise to choose a high magnification; however in practice, a magnification of 8x or 10x is usually more than enough. The advantage of a high magnification is that the image is a lot closer. The disadvantage of a high magnification is that the field of view (width of the field) and the light output is smaller and the light output is decreased as well. It is also difficult to hold binoculars with a magnification higher than 10x stable in your hand, they have to be placed on a tripod.
The twilight factor is calculated by multiplying the lens diameter and magnification.Then you need to take the square root of this (this is also indicated in our specifications). If you are in densely forested areas, or want to see animals that only appear at dusk (e.g. deer) it is wise to go for a viewer with a twilight factor of at least 15 (preferably higher). The twilight factor is also influenced by the coatings on the lens, the type of glass used and the coatings on the prisms. More expensive binoculars may have a lower twilight factor but usually give a much brighter picture than cheaper binoculars with a higher twilight factor.
Weight and dimensions
If you travel or go hiking a lot then compact binoculars are recommended. These are easy to carry and not so heavy on the neck. However, a compact viewer has a smaller lens and therefore a lower twilight factor. In addition, the field of view is smaller when you go for a high magnification (higher than 9x)
Porro or roof prism viewer?
The Powerview series is available as porro binoculars and roof prism binoculars. Porro binoculars (see diagram below) are broader binoculars and based on the first design of binoculars. The Porro consists of two rectangular prisms attached together so that the light is reflected three times, resulting in a correct image. The conventional binoculars use Porro Prisms.
A roof prism viewer uses a roof prism (see diagram below). This design is technically more complicated than a Porro prism design, as it uses prisms which must have very accurately polished edges. The light is reflected four times. This design is more compact, but because the light path is longer and the prisms more complicated, the quality of the glass and the manufacturing must be higher than that of the Porro Prism design. Only then can a equal performance be achieved. Roof Prism binoculars have straight tubes as shown in the picture.