JIS B7121:1985 pdfダウンロード。Prism Binoculars Scope This Japanese Industrial Standard specifies the binoculars using prismas erecting optical system, hereinafter referred to as the “binoculars” Remarks 1.This standard applies also to prism type binoculars usinga plane reflecting mirror instead of prism. 2The units and numerical values given in { } in thisstandard are in accordance with the International Systemof Units (SI)，and are appended for reference. Definitions For the purposes of this standard, following definitions apply: variable power type binocularThe binocular capable of changing the magnification. zoom type binocular The binocular capable of changing con-tinuously the magnification without variation of diopter bymoving a...