ICS 37.040.10                          MED 32

Superseding IS 9915 : 1981

Reaffirmed 2021

NATIONAL FOREWORD

This Indian Standard which is identical with ISO 517 : 2008 ‘Photography — Apertures and related properties pertaining to photographic lenses — Designations and measurements’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Photographic and Cinematographic Equipment Sectional Committee, and approval of the Mechanical Engineering Division Council.

This standard supersedes IS 9915 : 1981 ‘Lenses aperture markings, still cameras’. After publication of this standard, shall be treated as withdrawn.

The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are however not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice is to use a point (.) as the decimal marker.

For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis shall be rounded off in accordance with IS 2 : 1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.