BS ISO 3058:1998

Defines the characteristics for low-power magnifiers and gives recommendations for their selection for inspection of surfaces. Does not include watch-makers' loupes and spectacles, single-element, spherical- or cylindrical-lens magnifiers where either the lens or lens-mount rests on the surface of the object being examined (including magnifiers with any form of graduated scale for the purpose of measuring), plastic lens sacs, liquid filled, or magnifiers for examining internal surfaces.

1.1 This International Standard specifies the characteristics of the following types of low-power magnifiers and gives recommendations for their selection for the inspection of surfaces. Single-element magnifiers of magnification typically up to×4 (TypeA). Multi-element magnifiers of magnification typically up to×10 (TypeB). Twin-system magnifiers of magnification typically up to×15 (TypeC), categorized as follows: binocular, normally with a long working distance (TypeC.1); bi-ocular1), including those refined with stops or other attachments, for quasi-stereoscopic vision (TypeC.2). Concave-mirror magnifiers with front-surface reflectors in powers typically up to×6 (TypeD). 1.2 This International Standard is not concerned with: watch-makers\' loupes and spectacles; single-element, spherical- or cylindrical-lens magnifiers in which either the lens or the lens-mount rests on the surface of the object to be examined (this includes magnifiers provided with any form of graduated scale for the purpose of measurement); plastic lens sacs, liquid-filled; magnifiers intended for the examination of internal surfaces.