Steiner Optik 7x50 Commander Binoculars - Manuel (Page 18)

18
what really Matters:
One of the most important parameters of a high-
performance binocular is its light transmission, which
means the amount of light that ultimately reaches the
human eye.
In low light conditions such as in rain, dusk or dawn a
higher light transmission can make a decisive difference.
However, light transmission does not always equal bright-
ness. Each binocular has many different values for light
transmission, depending upon the wavelength of light
(color). Conventional binoculars tend to deliver limited
peak values only at a certain wavelength (for example:
blue) but lose other colors' transmission (for example: red)
of up to 30%. The result of such transmission peaks, are
color distortions - therefore high peak values will not
improve your binoculars but are actually counterproducti-
ve for a true bright color image.
However behind this relatively simple sounding issue lies a
substantial challenge. Optical lens coatings deliver high
transmission values only for a very specific wavelength. At
the same time, however, it can have adverse effects at
other wavelengths on light transmission, image sharpness
and depth of field. This is why higher quality binoculars
require multiple layers of lens coating that together result
in good performance for the most important colors.