Whether your hobby is hunting, visualizing the environment or you are a lover of outdoor activities, binoculars should be that accessory you always have to carry in your backpack.

Binoculars are probably the most widely used optical elements in the world, and for this reason, there are a variety of them with very different characteristics.

In this week’s article we are going to explain a little about what they are, what their most outstanding utilities are, and above all, offer an approximation of the products in our catalogue to help you choose the most suitable one according to your needs.

Internal elements of the binoculars

The differential factor when choosing a good prismatic is the fact of knowing the internal elements of these optical complements.

There are two systems of prisms, the classic ones, called Porro type, and the compact ones, also called Roof.

Porro prism system

It has a mechanical prism system, with a total reflection of light, which reduces the loss of light.

It has a characteristic 3D effect, due to the placement of premiums, and usually have a variable focus, but with a more accurate perception of depth.

Their particular internal structure makes these binoculars heavier and wider.

Roof prism system

The prisms are aligned in a linear way, so their structure is more ergonomic and lighter, which is why they are called compact.

The focus on near objects is less than in the classics, and have a partial reflection of light, so the transmission of the same is lower.

These binoculars are suitable for everyday use or, due to their internal prisms, for astronomy.

Points to bear in mind when choosing binoculars

Hood diameter and magnification

The following two features share many similarities with other precision optical elements such as conventional rifle scopes used for hunting or sport shooting activities: magnification and bell diameter.


All binoculars incorporate two numbers in their name, for example: Gamo 12×25 DCF. The first of the numbers indicates that their magnifications will be 12.

It may seem like a determining factor, but lens coatings, prism systems or the section we are going to talk about now will be more relevant to the final choice.

All the binoculars you will find in our catalogue have a really impressive number of magnifications.

Bell diameter

Returning to the example cited above, the Gamo 12X25 DCF prismatic incorporates a second number, which indicates the diameter of the bell, i.e. the measurement of the output tube.

This is a decisive factor when choosing a good prismatic, because the larger the diameter, the larger the field of vision will be and it will become a high-performance optical element in outdoor locations.

Light index

Another important feature, and very easy for any user to calculate, is the brightness index of the binoculars.

In order to calculate the relative brightness of the binoculars, the diameter of the lens has to be divided by the number of magnifications.

This is an important calculation, as it will result in the quality of binoculars in low-light environments.

  • Low luminosity: less than 3.5
  • Average brightness: between 3.5 and 4
  • High brightness: between 4 and 5 (bright binoculars)
  • Very high brightness: 6 or more than 6

Field of vision

The next point to consider is the field of vision, which will make the difference between mid-range binoculars and professional or high-end binoculars.

It is normally calculated at a distance of 1,000 metres, and the number varies according to the quality of the chosen optical instrument.

For example, a 10×25 will have a field of view of 35 meters, so that prismatic will cover a ground of that distance at 1,000 meters. The much higher quality Delta Optical Titanium 8X56 will cover a field of view of 98 meters at 1,000 meters to professional or high.


The penultimate outstanding factor of a prismatic lies in the focus, which is normally done through a turning action on a cylindrical part of the optical element.

Those instruments that have a minimum focusing distance of 6-8 meters, will be a great prismatic. If the minimum distance is reduced, the prism will be of better quality, since it will allow a very adequate visualization of elements at short distance.

Prisms material and lens sealing

The last outstanding functionality of a good prismatic is the material with which the prisms have been made and the sealing of the lenses.

There are optical instruments with prisms made of polymer, typical of low quality binoculars. Internal systems developed in boron glass (BK-7) and barium glass (BAK-4) are normally recommended, the latter being the best option for providing sharper images and with a better luminosity index.

After this small introduction, which is necessary due to the difficulty normally involved in choosing a good prismatic, it is important to point out that there are some characteristics that are less noteworthy, but equally important.

Multiple coating lenses, lens flip-over or external structure will also ensure that the product is of higher or lower quality.

Next, we will select two products from each range, designed for a wide range of activities.

Economic range: The choice for adventurers and outdoor enthusiasts

These types of binoculars are designed primarily with roof prism systems, so their structures are compact.

It will allow use in hostile environments with high humidity and also with rain, as its internal technologies make it possible to waterproof binoculars.

Their increases will range from 12 to 20, and are designed primarily for lovers of tourism, survival or small game.

Delta optical voyager collection

The Delta Optical Voyager Collection fulfils all the characteristics to be catalogued as high performance compact binoculars.

They have an anodized aluminum external body, designed to resist corrosion and high humidity.

In addition, they have roof prism system, which will ensure good sharpness and focus at medium distance.

Another key feature is the number of magnifications and the diameter of the bell, as the four models will have 10 zooms and 25 mm of bell, making them very valid options for tourism or survival activities that do not require an extremely wide field of vision.

You will be able to choose between the yellow, blue, red and black prismatic, so the chromatic diversity will be spectacular. It also incorporates a multi-position case made of nylon, to carry it in any type of trip or activity.