The fact that the objective lens size (42 mm.) and magnification (8x) are the same, means that some optical features are also exactly the same:
Light gathering ability: The light gathering ability of a binocular is determined by the size of the objective lens and since all four have the same aperture (42 mm.), their light gathering ability is the same.
Twilight factor: The ability of a binocular to perform in low light conditions is also expressed in the so-called “Twilight factor” (sq. root of aperture x magnification) and this is also the same: 18.33.
Relative Brightness Index: The exit pupil (aperture/magnification: 42/8 = 5.25) is also the same in all the cases. This means that the Relative Brightness Index (RBI) (sq. of exit pupil) is also the same: 27.56. So, as far as these two important factors are concerned, the brightness of the image delivered to the viewer’s eyes should be the same irrespective of price of the instrument.
However, in the end the quality of the optical glass and the optical coatings will make all the difference between the binoculars from the different price ranges as far as image quality is concerned.
The Bushnell 8×42 binoculars have already been reviewed in comparison with other 8×42 binoculars in different price ranges, viz. Budget range, $150+ range, $250+ range and $400+ range.
Now, however, the different Bushnell 8×42 binoculars will be compared to one another.
The budget Bushnell 8×42 binoculars will be reviewed together:
Then two Bushnell Legend 8×42 binoculars:
Then the Bushnell Excursion Ex 8×42
Finally the top-of-the-range Bushnell Elite e2 8×42 Binocular.