The zoom will be just as bright at 27x and brighter at magnifications below this. The only fixed eyepiece in the Nikon range of wideangles which has equally good light transmission to the zoom is the lowest magnification one (20x/24x/30x). However, the zoom might seem less bright because the field of view is so much narrower. With a wider field of view, more light falls on the retina spread out over a larger area, but the light intensity from any given object within the field is no greater. In practice all the Nikon Fieldscope eyepieces (including the zoom) have such a high light transmission that only the magnification (i.e. exit pupil) influences image brightness.
Last edited by kabsetz : Tuesday 16th October 2007 at 10:15.
Reason: correction of data