Calculation Twilight number and statement on twilight performance for binoculars

The visual acuity of the human eye decreases with age. TwilightFor night glasses, which are ideal for sitting game and as sow glasses, the light intensity is the most important feature. " More info to around a third of daytime visual acuity. The eye's sensitivity only increases for the blue spectral range. In order to be able to recognise details over long distances even in twilight, binoculars with high MagnificationThe magnification of a binocular model is perhaps the most misunderstood feature. High magnification can be useful! " More info and corresponding twilight performance (e.g. 10×56 or 8×56). The twilight number and thus the Calculated luminous intensity and results from Enlargement and Lens diameterThe larger the lens diameter, the more light can be absorbed by the lens of the optical system. Glass purity plays a major role. " More info of binoculars:

Formula for calculating the twilight power of binoculars

8×56 binoculars have a twilight factor of 21.2, which means that you can still see an object at a distance of 212 metres. The twilight factor gives a purely calculated value for the image brightnessbut which is also characterised by the optical construction, different types of glass and the quality of the RemunerationIf light hits a glass-air surface (e.g. with a roof prism), the reflection causes a loss of light. " More info is influenced. Important: One High twilight number stands not simultaneously for high or good twilight performance! A 30×75 spotting scope, for example, with the impressive twilight index of 47.4 is equipped with a Exit pupilIn addition to the twilight number, the binocular exit pupil at the eyepiece of the binoculars is also very important for seeing in twilight (twilight vision). " More info (see below) of only 2.5 mm is not suitable for twilight observations.