ISO/TC 172/SC 1 - Fundamental standards

This document specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices), under equivalent conditions, for their ability to resist the influence of mechanical stress. The purpose of the testing is to investigate to what extent the optical, climatic, mechanical, chemical, and electrical (including electrostatic) performance characteristics of the specimen are affected by mechanical stress.

This document provides rules for the measurement of the spectral reflectance of plane surfaces and the spectral transmittance of plane parallel elements using spectrophotometers. This document only applies to measurements of the regular transmittance and the regular reflectance; it does not apply to those of the diffuse transmittance and the diffuse reflectance. This document is applicable to test samples, which are coated or uncoated optical components without optical power.

This document specifies rules for presentation of aspheric surfaces and surfaces with low order symmetry such as cylinders and toroids in the ISO 10110 series, which standardizes drawing indications for optical elements and systems. It also specifies sign conventions and coordinate systems. This document does not apply to off-axis aspheric and discontinuous surfaces such as Fresnel surfaces or gratings. NOTE For off-axis aspheric and non-symmetric surfaces, see ISO 10110-19. This document does not specify the method by which conformity with the specifications is tested.

This document specifies rules for the indication of the surface texture of optical elements, in the ISO 10110 series, which standardizes drawing indications for optical elements and systems. Surface texture is the characteristic of a surface that can be effectively described with statistical methods. Typically, surface texture is associated with high spatial frequency errors (roughness) and mid-spatial frequency errors (waviness). This document is primarily intended for the specification of polished optics. This document describes a method for characterizing the residual surface that is left after detrending by subtracting the surface form. The control of the surface form specified in ISO 10110-5, ISO 10110-12, and ISO 10110-19 is not specified in this document.

This document specifies the general layout of drawings and provides examples of indications in the ISO 10110 series, which standardizes drawing indications for optical elements and systems. This document specifies the presentation in drawings of the characteristics, including the tolerances, of optical elements and systems. This document also includes the popular tabular format, formerly presented in ISO 10110‑10. This tabular format, now described in 5.1, is the preferred format for ISO 10110 drawings. Rules for preparation of technical drawings as well as for dimensioning and tolerancing are given in various ISO Standards. These general standards apply to optical elements and systems only if the necessary rules are not given in the various parts of ISO 10110.

This document gives fundamental explanations to interferometric measurement objects, describes hardware aspects of interferometers and evaluation methods, and gives recommendations for test reports and calibration certificates.

This document specifies general optical test methods for the measurement of the relative irradiance in the image field. This document is applicable to optical imaging systems in the optical spectral region from λ = 100 nm to λ = 1 μm. Theoretical reflections and the comparison with the calculation apply only to optical systems. This document is applicable to rotationally invariant and rotationally variant systems; anamorphic systems, for example, are included. Telescopic systems are also included. The title of this document refers to the relative irradiance in the image field, but this document is also applicable to determination of the relative radiant power. NOTE For telescopic systems, it is suitable to state only the radiant power; for most imaging systems, the conversion from radiant power to irradiance is easy. As far as measurements are concerned, this document is also applicable to electro-optical systems. The two methods described differ particularly in the influence of veiling glare.

This document specifies procedures for determining the spectroscopic forward scattering characteristics of coated and uncoated optical surfaces over a specified wavelength range between 350 nm and 850 nm using a double-beam spectrophotometer with an integrating sphere. This document is also applicable to the forward scattering properties at a single wavelength. This document is applicable to spectroscopic forward scattering measurements with collection angles larger than 2,7 degrees. ISO 13696 provides a measurement method for smaller collection angles.

This document specifies the indication of tolerances for four categories of imperfections within optical materials — stress birefringence, bubbles and inclusions, homogeneity, and striae — in the ISO 10110 series, which standardizes drawing indications for optical elements and systems. Tolerances are applied either to a finished optical part, a finished system of optical parts, or to the raw material used to manufacture an optical part.

This document specifies rules for the indication of the permissible deformation of a wavefront transmitted through or, in the case of reflective optics, reflected from an optical element or assembly in the ISO 10110 series, which standardizes drawing indications for optical elements and systems. This document is also applicable when using optical systems with general surfaces (ISO 10110-19). The deformation of the wavefront refers to its departure from the desired shape. The tilt of the wavefront with respect to a given reference surface is excluded from this document. There is no requirement that a tolerance for wavefront deformation is indicated.

ISO 8478:2017 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 ISO 8478:2017, the wavelength range reads 370 nm to 680 nm. ISO 8478:2017 is also applicable to mirror lenses (see Annex A).

ISO/TR 21477:2017 intends to guide the user to understand the origins, meanings and differences between the two systems of specifying and evaluating surface imperfections in ISO 10110-7 and ISO 14997, specifically the dimensional method and the visibility method, and to provide information on how to use them. Tables are provided to show specifications of roughly equivalent yield loss for imperfections in the two systems.

ISO 14997:2017 specifies the physical principles and practical means for the implementation of methods for evaluating surface imperfections. For imperfections specified using the visibility method, two inspection methods are described. The first is visual evaluation of the surface without any comparison standard (IVV). The second is a visibility assessment of a surface imperfection when compared to an artefact of known brightness (ISV). For imperfections specified using the dimensional method, three methods are described. The first is visual evaluation of the surface without any comparison standard (IVD). The second is a dimensional assessment of a surface imperfection when compared to an artefact of known size (ISD). The third is the dimensional measurement of a surface imperfection using magnification and either a comparison artefact of known size or a reticle or ruler (IMD). Instruments exist that allow objective measurement of brightness (digital scatterometry) or size (digital microscopy). While these instruments can be used for evaluation of surface imperfections, they are beyond the scope of this document. ISO 14997:2017 applies to optical surfaces of components or assemblies such as doublets or triplets. ISO 14997:2017 can be applied to optical plastic components; however, attention is drawn to the fact that impact damage to plastic materials often looks very different from that on harder materials as it does not always result in the removal of material but instead can displace material, causing ripples in the surface. Consequently, visual comparisons of scratch and dig damage to plastic with those on glass or crystalline materials can give very different results.

ISO 10110 (all parts) specifies the presentation of design and functional requirements for single optical elements and for optical assemblies in technical drawings used for their manufacture and inspection. ISO 10110-7:2017 specifies the indication of the level of acceptability of surface imperfections within a test region on individual optical elements and optical assemblies. These include localized surface imperfections, edge chips and long scratches. The acceptance level for imperfections is specified, taking into account functional effects (affecting image formation or durability of the optical element), as well as cosmetic (appearance) effects. ISO 10110-7:2017 applies to transmitting and reflecting surfaces of finished optical elements, whether or not they are coated, and to optical assemblies. It allows permissible imperfections to be specified according to the area affected by imperfections, or alternatively by the visibility of imperfections, on components or in optical assemblies.

ISO 9022-23:2016 specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices), under equivalent conditions, for their ability to resist the influence of low pressure combined with cold, including the potential condensation and freezing of moisture, ambient temperature, and dry or damp heat. It is applicable to optical instruments including additional assemblies from other fields, designed for operation and/or transport in high mountainous areas or on board aircraft or missiles. The purpose of the testing is to investigate to what extent optical, climatic, mechanical, chemical, and electrical (including electrostatic) performance characteristics of the specimen are affected by combined low pressure and low, ambient, or high temperature. Furthermore, the additional effects of moisture condensing and freezing on the instrument or components can be determined. Examples are instruments which are installed or externally mounted on aircraft or missiles or transported inside aircraft or flying objects not providing any pressure equalization. Annex A explains the intent of the different types of tests.

ISO 9022-1:2016 defines terms relating to environmental tests of optical and photonic instruments, including additional assemblies from other fields (e.g. mechanical, chemical and electronic devices), and specifies basic features of testing.

ISO 10110-9:2016 specifies the presentation of design and functional requirements for optical elements and systems in technical drawings used for manufacturing and inspection. It specifies rules for indicating the treatments and coatings applied to optical surfaces for functional and/or protective purposes.

ISO 10110-11:2016 specifies the presentation of design and functional requirements for optical elements and systems in technical drawings used for manufacturing and inspection. It specifies the permissible deviations and material imperfections when these are not explicitly indicated.

ISO 9022-9:2016 specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical and electronic devices), under equivalent conditions, for their ability to resist the effects of simulated solar radiation or laboratory weathering, which is a combination of simulated solar radiation, heat, and moisture. It is applicable to instruments that may be exposed to sunlight during operation or unsheltered storage on the earth's surface, or in the lower atmosphere. The purpose of testing is to investigate to what extent the optical, climatic, mechanical, chemical and electrical (including electrostatic) performance characteristics of the specimen are affected by solar radiation or weathering (solar radiation, heat, and moisture).

ISO 10110-6:2015 specifies the presentation of design and functional requirements for optical elements and systems in technical drawings used for manufacturing and inspection. ISO 10110-6:2015 specifies rules for indicating centring tolerances for optical elements, subassemblies, and assemblies. ISO 10110-6:2015 applies to plano surfaces, rotationally invariant surfaces, circular cylindrical, non-circular cylindrical, and non-symmetrical surfaces (general surfaces). General surfaces are described using ISO 10110‑19.

ISO 10110-19:2015 specifies the presentation of design and functional requirements for optical elements and systems in technical drawings used for manufacture and inspection. ISO 10110-19:2015 provides a general method of describing surfaces and components. This part of ISO 10110 applies to continuous and discontinuous surfaces. It does not apply to diffractive surfaces, Fresnel surfaces, ophthalmic glasses, and micro-optical surfaces. ISO 10110-19:2015 applies to any general surface or component, even including spherical or rotationally symmetric surfaces if it is necessary, i.e. when NURBS, splines, point clouds, etc. are used. ISO 10110-19:2015 does not specify the method by which compliance with the specifications is to be tested.

ISO 10110-5:2015 specifies the presentation of design and functional requirements for optical elements and systems in technical drawings used for manufacturing and inspection. ISO 10110-5:2015 specifies rules for indicating the tolerance for surface form deviation. NOTE The terminology of interferometry employing the unit "fringe spacings" is widely used for the specification of tolerances. However, the usage of non-interferometric methods for testing of optical parts has recently become more important. Therefore, unlike in the earlier versions of this part of ISO 10110, nanometres shall now be the preferred and standard unit to express surface form deviations. The usage of fringe spacings is still permitted given that the base wavelength is explicitly stated. ISO 10110-5:2015 applies to surfaces of plano, spherical, aspheric, circular and non-circular cylindric, and toric form as well as to surfaces of other non-spherical shape such as generally described surfaces. It does not apply to diffractive surfaces, Fresnel surfaces, and micro-optical surfaces.

ISO 14999-4:2015 applies to the interpretation of interferometric data relating to the measurement of optical elements. ISO 14999-4:2015 gives definitions of the optical functions and values specified in the preparation of drawings for optical elements and systems, made in accordance with ISO 10110‑5 and/or ISO 10110‑14 for which the corresponding nomenclature, functions, and values are listed in ISO 10110‑5, Annex B. It also provides guidance for their interferometric evaluation by visual analysis.

ISO 10109:2015 contains tables for environmental tests and test parameters which can be used as a guideline for the selection of environmental tests. These include the selection of standardized tests according to ISO 9022 as well as additional parameters not described in ISO 9022 and necessary for the optical or photonic instruments. Ultimately, these tables specify the requirements to be met with regard to the reliability of the optical, mechanical, chemical, and electrical properties or performance characteristics of the instruments when exposed to environmental influences.

ISO 9022-11:2015 specifies the methods relating to the environmental tests of optical instruments, including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices) under equivalent conditions, for their ability to resist the influence of mould growth. However, complete instruments or assemblies are only tested as specified in ISO 9022-11:2015 in exceptional cases. Normally, representative specimens such as mounted optics, material samples, or surface coatings on representative samples are used for testing. The tests described in ISO 9022-11:2015 are designed for the selection of materials and components for instruments likely to be used in an environment that is conducive to mould growth, rather than for regular production control. The purpose of testing is to investigate to what extent the optical, climatic, mechanical, chemical and electrical (including electrostatic) performance characteristics of the specimen are affected by mould growth. In addition, the tests in ISO 9022-11:2015 are designed to assess to what extent metabolic waste products (such as enzymes or acids) excreted by fungi, cause etching, corrosion, or short-circuits on, for instance, printed circuit boards.

ISO 9022-12:2015 specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices), under equivalent conditions, for their ability to resist the influence of contamination, i.e. contact with corrosive chemical substances (hereafter called test agents). However, complete instruments or assemblies are only tested as specified in ISO 9022-12:2015 in exceptional cases. Normally, representative samples such as material items or surface coatings on representative substrates are used for testing. The tests described in ISO 9022-12:2015 are designed for the selection of materials and components for instruments likely to suffer contamination during service life, rather than for regular production control. The purpose of testing is to investigate the resistance of an instrument and, in particular, of instrument surfaces, coatings, or synthetic materials, to a short exposure to the test agents.

ISO 9022-14:2015 specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices) under equivalent conditions, for their ability to resist the influence of dew, hoarfrost or ice. The purpose of testing is to investigate to what extent the optical, climatic, mechanical, chemical, and electrical (including electrostatic) performance characteristics of the specimen are affected by dew, hoarfrost, or ice.

ISO 9022-17:2015 specifies the methods relating to the environmental tests of optical instruments and including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices) under equivalent conditions, for their ability to resist the influence of combined contamination and solar radiation. "Contamination", as used in ISO 9022-17:2015, means the contact of optical instruments with corrosive chemical substances (hereafter called test agents). Complete instruments or assemblies are, however, not be tested to ISO 9022-17:2015 except for special reasons (refer to ISO 9022-12). As a rule, representative substrates are used as specimens. The tests described in ISO 9022-17:2015 are designed for the selection of materials and components for instruments likely to be subjected to combined contamination and solar radiation during service life, rather than for regular production control. The purpose of testing is to investigate the resistance of an instrument, and in particular, of instrument surfaces, coatings, or synthetic materials, to a short-time exposure to the test agents combined with solar radiation.

ISO 9022-2:2015 specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices), under equivalent conditions, for their ability to resist the influence of temperature and/or humidity. The purpose of the testing is to investigate to what extent optical, climatic, mechanical, chemical, and electrical (including electrostatic) performance characteristics of the specimen are affected by temperature and/or humidity.

ISO 9022-6:2015 specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices), under equivalent conditions, for their ability to resist the influence of blowing dust. The purpose of testing is to investigate to what extent the optical, climatic, mechanical, chemical, and electrical (including electrostatic) performance characteristics of the specimen are affected by blowing dust, especially with a view to malfunctions of moving parts (such as sliding surfaces, bearings, contacts, operating controls, gears) or unacceptable wear of surfaces. This test is not intended to determine the wear resistance to coarse dust.

ISO 9022-7:2015 specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices), under equivalent conditions, for their ability to resist the influence of drip or rain. The purpose of testing is to investigate to what extent the optical, climatic, mechanical, chemical, and electrical (including electrostatic) performance characteristics of the specimen are affected by drip or rain. Contamination of drip or rain water due to impurities in the air is to be ignored for the purposes of ISO 9022-7:2015.

ISO 9022-8:2015 specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices), under equivalent conditions, for their ability to resist the influence of high pressure, low pressure, or immersion. The purpose of testing is to investigate to what extent the optical, climatic, mechanical, chemical, and electrical performance characteristics of the specimen are affected by high pressure, low pressure, or immersion.

ISO 9022-20:2014 specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices), under equivalent conditions, for their ability to resist the influence of sulfur dioxide (SO2) or hydrogen sulfide (H2S) in a humid atmosphere. The purpose of the testing is to investigate to what extent optical, climatic, mechanical, chemical, and electrical performance characteristics of the specimen are affected by sulfur dioxide or hydrogen sulfide. ISO 9022-20:2014 is not applicable to the testing of material and surface coatings for their corrosion resistance using high concentrations of sulfur dioxide, for which representative samples are generally used as specimens. The appropriate material standards apply to tests of this type.

ISO 9022-4:2014 specifies the methods relating to the environmental tests of optical instruments including additional assemblies from other fields (e.g. mechanical, chemical, and electronic devices), under equivalent conditions, for their ability to resist the influence of salt mist. Exposure to salt mist mainly results in the corrosion of metals. Effects might also occur by way of clogging or binding of moving parts. The purpose of the testing is to assess, as early as possible, the ability of the instrument, and particularly of the surfaces and protective coatings of the instrument, to resist the effects of a salt atmosphere. Normally, representative samples or complete small units are used for testing. Complete large instruments or assemblies are only tested as specified in this part of ISO 9022 in exceptional cases.

ISO/TR 16743:2013 gives terms and definitions and describes techniques for the characterization of wavefronts influenced by optical systems and optical components. It describes basic configurations for a variety of wavefront sensing systems and discusses the usefulness of tests in different situations.

ISO 9335:2012 gives general guidance for the construction and use of equipment for measurement of the optical transfer function (OTF) of imaging systems. It specifies important factors that can influence the measurement of the OTF, and gives general rules for equipment performance requirements and environmental controls. It specifies important precautions that should be taken to ensure accurate measurements and correction factors to be applied to the collected data.

ISO 9022-22:2012 specifies methods for the testing of optical instruments, including additional assemblies from other fields (e.g. mechanical, chemical and electronic devices) under equivalent conditions, for their ability to resist combined bump or random vibration, in cold, dry heat or temperature change.

This part of ISO 25297 specifies the information requirements for optical systems and parts, and provides an information model to support the processes of optical design, optical evaluation and analysis for these optical systems and parts when using computers with CAD and CAE. NOTE Generally, an optical system means an optical unit as an optical product, which performs optical functions, and is composed of optical elements and the barrels in which these elements are mounted. In this part of ISO 25297, an optical system is a collection of optical parts and optical assemblies, e.g. the viewfinder system or the taking lens system of a leaf shutter camera. This information model adds the data peculiar to optical design specification based on STEP to ISO 10303 (all parts). The additional information is product specification information, optical design information, optical evaluation information and analysis information. This part of ISO 25297 is generically called the Neutral Optical Data Interchange Format (NODIF). The following are within the scope: — information on product specification, optical design, optical evaluation and analysis; — optical systems and parts in imaging systems, such as cameras and copiers, viewing systems for telescopes and microscopes and the other optical systems, such as projectors and pick-up lenses; — multiple-configuration optical systems, including zoom lenses and inner focusing systems; — optical path definition, including ray-path sequence and optical surface arrangement; — optical assemblies, including cemented parts and dynamic parts; — mathematical description of the optical surface form; — description of diffractive surfaces; — machining process designation, such as polishing, molding or replicating; — optical material specifications, such as material names, lot numbers and measured refractive indices; — optical tolerances for the shape and material property of each optical part; — assembly tolerances, such as separation, parallelism, displacement and tilt. — effective diameters, coatings and protective surface treatment; — paraxial evaluation, such as focal length, back focal length, principal points and f-number; — ray-tracing evaluation, such as geometrical ray-tracing results (i.e. ray directions and intersection points on each surface and optical path lengths), aberrations and wavefront aberration; — OTF evaluation based on geometrical and/or physical optics; — illuminance distribution on a detection surface or a projection surface; — spectral characteristics; — ghost image evaluation; — thermal analysis accompanying optical surface deformation and material property value change; — stress analysis accompanying optical surface deformation and material property value change; — veiling glare and surface imperfections. The following are outside the scope of this part of ISO 25297: — mechanical design, electronic design and embedded software design; — optical systems in which the optical path is changeable, e.g. beam splitters or variable magnification converters; — tolerances for mechanical parts; — parts with a diameter less than 10 times the wavelength of light; — parts made from materials whose dielectric constant, σ, electric permittivity, ε, and magnetic permittivity, μ, are uninfluenced by interaction between the materials and the light; — graphical documents resulting from design, evaluation and analysis of products; — optical wave guide for optical communications; — product planning information concerning market research and customer analysis; — product definition and configuration control information irrelevant to design, evaluation and analysis; — analysis information, except thermal and stress analysis, e.g. vibration analysis; — information on trial production, production process including production planning and production control, and processes after production, such as shipment and repair; — ophthalmic optics.

ISO 25297-2:2011 specifies the relationship between the terms used in ISO 25297-1 and the properties defined in ISO 23584-2 and provides the means to facilitate the use of both standards.

ISO 15529:2010 specifies the principal MTFs associated with a sampled imaging system, together with related terms, and outlines a number of suitable techniques for measuring these MTFs. It also defines a measure for the “aliasing” related to imaging with such systems. ISO 15529:2010 is particularly relevant to electronic imaging devices such as digital still and video cameras and the detector arrays they embody.

ISO 9336‑1:2010 specifies a method of testing interchangeable lenses for 35 mm still cameras with a picture format of 24 mm x 36 mm in terms of imaging states aimed at making valid optical transfer function measurements.

ISO 517:2008 pertains to apertures and related properties of photographic lenses affecting the illuminance at the centre of the image. ISO 517:2008 specifies aperture markings for all types of lenses used in still cameras, and gives tolerances for the stop numbers. It also defines aperture stop, entrance pupil, focal length, relative aperture and stop numbers, and gives methods for their measurement or determination. ISO 517:2008 applies only to lenses focused on objects at infinity; that is, at least 50 times the focal length of the lens.

ISO 9039:2008 specifies methods of determining distortion in optical systems for the purposes of quality evaluation. It applies to optical imaging systems in the optical spectral range from 100 nm to 15 000 nm which, by their design, aim at a rotationally symmetric image geometry. It is applicable to electro-optical imaging systems provided that adequate rotational symmetry of the image is guaranteed. It does not, therefore, apply to anamorphic and fibre optic systems.

ISO/TR 14999-3:2005 discusses sources of error and the separation of errors into symmetric and non-symmetric parts. It also describes the reliance of measurements on the quality of a physical reference surface and the development of test procedures capable of achieving absolute calibration.

ISO/TR 14999-1:2005 gives terms, definitions and fundamental physical and technical relationships for interferometric measurements of optical wavefronts and surface form of optical elements. It explains, why some principles of the construction and use of interferometers are important due to the wave nature of the wavefronts to be measured. Since all wavefronts with the exception of very extended plane waves do alter their shape when propagating, ISO/TR 14999-1:2005 also includes some basic information about wave propagation. In practice, interferometric measurements can be done and are done by use of various configurations; ISO/TR 14999-1:2005 outlines the basic configurations for two-beam interference. The mathematical formulation of optical waves by the concept of the complex amplitude as well as the basic equations of two-beam interference are established to explain the principles of deriving the phase information out of the measured intensity distribution, either in time or in space. Both random and systematic errors may affect the results of interferometric measurements and error types to be clearly differentiated are therefore described in ISO/TR 14999-1:2005.

ISO 10110-17:2004 specifies rules for the indication of the damage threshold from laser irradiation up to which optical surfaces shall not exhibit any damage, as defined in ISO 11254-1, as part of specification of the presentation of design and functional requirements for optical elements and systems in technical drawings used for manufacturing and inspection.

This International Standard defines terms relating to chromatic aberrations and indicates the mathematical relationships between those terms. It also gives general guidance for the measurement of chromatic aberrations and is valid for optical imaging systems which are constructed to be of rotational symmetric imaging geometry. It is also valid for optoelectronic imaging systems.

Adopts both the veiling glare index (VGI) and the glare spread function (GSF) as measures of the veiling glare characteristics of optical and electrooptical imaging systems. Laboratory measurement techniques are described in general terms and recommendations are made regarding the performance of the main subunits of the equipment. The measurement techniques described are chiefly valid for the visual spectral range. Also gives guidelines for the operation of measuring equipment such that accurate results can be achieved.