Binoculars 8x42 Pro

The first number (e.g."10x" or"8x") indicates the magnification, i.e. how often closer an object appears compared to the naked eye. The second number (e.g."42") refers to the diameter of the front lens in millimeters, which affects how much light can enter the binoculars.

The diopter adjustment makes it possible to compensate for differences in vision between both eyes. Rollei binoculars have a diopter ring on the right eyepiece. To adjust it, close your eye on the diopter side and focus with the other eye. Then open your previously closed eye and use the diopter ring to adjust the focus until the image is clear.

It is important to clean the lenses carefully to avoid scratches. Start by using a blower or brush to remove dust. Then use special lens cleaning wipes or solutions. The housing can be cleaned with a slightly damp cloth. Store the binoculars in a dry place and avoid extreme temperatures.

The field of view of binoculars indicates how wide the observable area is at a certain distance. It describes the section of the landscape that you can see through the binoculars. The field of view is an important parameter for assessing the performance and suitability of binoculars for specific applications. There are two common methods of describing the field of view: 1. Field of view in meters: This indicates the width of the observed area in meters when standing at a distance of 1,000 meters from the object being observed. For example, a field of view of 131 meters at 1,000 meters means you can see a width of 131 meters at a distance of 1,000 meters. 2. Field of view in degrees: This describes the observable angle of the field of view. For example, a field of view of 7.5° means you can see a conical section of the landscape at a 7.5° angle. A larger field of view is often desirable because it allows you to see more of your surroundings and more easily track moving objects, such as birds or sporting events. However, a very wide field of view can come at the expense of other optical properties, so it's important to find the right balance for your specific needs.

Light transmittance and twilight index are important terms related to binoculars that help assess the performance of the binoculars under different lighting conditions. 1. Light transmission: Light transmission describes what percentage of the incident light passes through the binoculars and ultimately reaches the viewer's eye. It is usually given as a percentage. For example, binoculars with a light transmission of 88% mean that 88% of the incident light passes through the binoculars, while the remaining 12% is lost through reflection, absorption or scattering. A high light transmittance value is desirable, especially for low-light observations, as it results in a brighter image. 2. Twilight index: The twilight index indicates how well binoculars work in dim light, such as at dusk. It is a measure of the brightness of the image that you see through the binoculars. A high twilight index indicates that the binoculars perform better in low light conditions. However, it is important to note that the twilight index is only a theoretical value and other factors, such as the quality of the lens coating and the overall construction, also play a role. In summary, both light transmission and twilight index are important indicators of the performance of binoculars in different lighting conditions. However, these values ​​should be considered in combination with other factors such as lens coating or construction and the user's individual needs to make the best choice.