ISO 8478:2017 光学およびフォトニクス—カメラレンズ—ISOスペクトル透過率の測定 | ページ 2

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, 2 (see www.iso.org/directives ).

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This document was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 1, Fundamental standards.

This second edition cancels and replaces the first edition (ISO 8478:1996), of which it constitutes a minor revision.

The main changes compared to the previous edition are as follows:

• the document has been updated to current drafting rules;
• A.2 b) has been adjusted.

Introduction

This document describes a preferred method for the measurement of spectral transmittance. Alternative methods may be used, provided that the method gives the same result as that obtained according to this document within the tolerances allowed by it. In the case of lenses with very long or short focal lengths and in large aperture lenses, care should be taken to maintain the ideal integration properties of the integrating sphere.

Spectral transmittance of the lens under test may vary with the diameter of the incident beam and with the angle of incidence of the beam. In order to obtain uniform results, this document specifies that the measurement is to be made with a collimated beam incident upon the lens along its optical axis, and filling the central half diameter of its entrance pupil at its minimum f-number.

In the case of lenses with very long or short focal lengths, the measuring method specified in this document may not be applicable due to the difficulty in preparing a very big or very small integrating sphere. In such a case, an alternative method may be used, provided that it gives the same result as that obtained according to this document within the tolerances allowed by this document.

Annex A, which forms an integral part of this document, is provided to give a particular method for measuring the spectral transmittance of mirror lenses.

1 Scope

This document specifies a method for measuring the spectral transmittance of camera lenses. It describes particular conditions for measuring the axial spectral transmittance, over a wavelength range from 350 nm to 700 nm, of camera lenses which are intended to be used mainly for taking pictures of very distant objects.

If the spectral transmittance values are used exclusively for the calculation of the ISO colour contribution index (see ISO 6728) throughout this document, the wavelength range reads 370 nm to 680 nm.

This document is also applicable to mirror lenses (see Annex A).

2 Normative references

There are no normative references in this document.

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Bibliography