Using 3D high magnification optics provides a lovely effect of a highly magnified view through the scope in the centre of the screen, with a normal magnification view displaying the peripheral view of the surroundings.
However, a trade off of this feature is the picture in picture view through the scope has significantly reduced viewing distance compared to the unmagnified peripheral view, even though distant objects are more easily seen through the scope.
View distance for the terrain and objects in 2D sights remains unchanged.

OBS:
View distance for the terrain and objects is reduced through the high magnification sight view.
View distance for the terrain and objects in peripheral unmagnified view remains unchanged.

EXP:
View distance for the terrain and objects through the high magnification sight view should not reduce below that of unmagnified view.
If something needs to be done to improve graphics performance, the view distance for the terrain and objects, level of detail etc for the peripheral unmagnified can be brutalised as it's not the user's visual focus.