Holger Merlitz
Well-known member
Ok, the specs of the HD-B models point in that direction,
their FOV seems rather "modest" (but slightly better than the predecessor) and not really wide-angle. The 8x42 have a 130m FOV and the 10x42 114m. The 8x56 have a 118 m FOV. The only test I have seen on HD-B (8x42) is kikkertspesialisten and they gave them better on edge sharpness than SLC 56mm and Zeiss HT 54mm, and they were ranked very high on resolution, contrast (12) and high (11) on brightness. So the optics seem to be very good.
So most likely the Perger-prisms would not be the first-hand choice in a super-wide binocular.
The Perger Porro may be used in wide angle instruments, no problem. It is true that, when compared to a Porro I or Porro II of identical entrance width, the Perger prism has a bottleneck at the contact surface of both prism elements. Yet, that doesn't necessarily imply vignetting, because the light cone is often narrower at this point than at the prism entrance. If in fact an unwanted amount of vignetting occurs, then there is no harm with the selection of a somewhat larger prism: A Perger prism with 10% increased entrance width leads to a binocular which is still smaller than a traditional Porro binocular with original (slightly smaller) prism size. So no big deal.
Cheers,
Holger