Tasco Essentials 7×50 Binocular
The Tasco Essentials 7×50 Binocular are multi-coated and not fully multi-coated like more expensive options, the combination of a moderate 7x magnification, large 50mm objective lenses and the use of Porro prisms instead of roof prisms make this a classic configuration for a low cost binocular that will perform well even in low light conditions and here is why:
Firstly, like the large windows in your house, larger lenses like the 50mm ones used on these binoculars are able to capture and let in more light than smaller ones.
Then the 7x magnification in combination with the 50mm objective lenses produces a very large 7.1mm exit pupil. This means that the shaft of light exiting the ocular lens will match your pupil’s diameter even in very low light when they are at maximum dilation and thus ensures that they are being supplied with enough light for you to perceive a bright image.
Lastly, the simpler design of the Porro prism means that these do not require the expensive mirror coatings needed on roof prism binoculars to achieve total internal reflection. So whilst this design of binocular may not look as modern as a roof prism, the result is that it simply costs less to achieve a bright image when using Porro prisms.
Another advantage of the very modest 7x magnification is that it results in a very wide viewing angle. At 7.1 °, this is very impressive and makes finding and then following small, fast-moving subjects like birds much easier, especially when at close range which is where the strength of this binocular lies.
The only downside to this design is that at 15ft (4.6m), the minimum focus distance on this binocular is relatively long.
The Zip focus system allows you to move through the entire focus range in less than a half-turn of the focus wheel–an excellent feature for following fast action. They are especially suited for use over water, snow and in other bright conditions.