It looks to me as if a bigger field of view can be obtained by using a shorter eye relief.
It's sort of intuitive.
Likewise, you might get more FOV by making the ocular lens diameter bigger.
If you could compromise on eye relief you could offer a better field of view.
This might be the case with rimfire shooting and specially with airguns.
In fact, one manufacturer makes an airgun scope with essentially no eye relief - the "Touch" !
Its field of view is twice that of a comparable model with a more normal eye relief.
Compared to the entry level Vantage SF, shortening the eye relief from 89mm to 76mm in the Airmax SF increases the FOV by 40%. Bringing the eye relief down to 30mm (like binoculars) in the Airmax 30 Touch more than doubles the field of view.
Vantage SF 3-12x44 89mm 10.2 - 2.6 m@100m
Airmax SF 3-12x40 76mm 14.6 - 3.6 m@100m
Airmax Touch 3-12x32 30mm 21.3 - 6.1 m@100m
Bookmarks