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1、BRITISH STANDARD BS ISO 2827:1988 Implementation of ISO 2827:1988 Photography Electronic flash equipment Determination of light output and performance UDC 771.448 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:44:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 2827:1988 This British
2、Standard, having been prepared under the direction of the Consumer Products and Services Sector Board, was published under the authority of the Standards Board and comes into effect on 15 October 1995 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference C
3、PW/42 Draft for comment 86/40121 DC ISBN 0 580 24850 X Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee CPW/42, Photography International coordination, upon which the following bodies were represented: British Film Institu
4、te British Institute of Professional Photography British Photographic Association Sira Limited The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Chartered Institution of Building Services Engineers Lighting Industry Federation Ltd. Amendmen
5、ts issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:44:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 2827:1988 BSI 01-2000i Contents Page Committees responsibleInside front cover National forewordii Forewordiii Text of ISO 28271 Licensed
6、Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:44:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 2827:1988 ii BSI 01-2000 National foreword This British Standard reproduces verbatim ISO 2827:1988 and implements it as the UK national standard. It supersedes BS 5841-7:1980 which is withdrawn.
7、This British Standard is published under the direction of the Consumer Products and Services Sector Board whose Technical Committee CPW/42 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals
8、 for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, BSI, 389 Chiswick High Road, London W4 4AL. A British Sta
9、ndard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover
10、, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 7 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldu
11、n sheffieldun, na, Sun Nov 26 12:44:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:44:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 2827:1988 (E) ii BSI 01-2000 Contents Page Forewordiii 1Scope and field of application1 2References1 3Defin
12、itions1 4Test conditions2 5Conditioning of flash equipment3 6Selection of operating mode3 7Method of measurement3 8Performance4 Annex Additional data6 Table Distance range7 Descriptors: Photography, photographic equipment, flash equipment, flash lamps, electronic flash tubes, tests, performance test
13、s, determination, light emission. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:44:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 2827:1988 (E) BSI 01-2000iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
14、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, govern
15、mental 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. Draft International Standards adopted by the technical committees are circulated to the
16、member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 2827 was prepared by Technical Committee ISO/TC 42, Photograp
17、hy. This second edition cancels and replaces the first edition (ISO 2827:1973), of which it constitutes a technical revision. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its lates
18、t edition, unless otherwise stated. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:44:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:44:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 2827:1988 (E) BSI 01-20001 1 Scope an
19、d field of application This International Standard specifies methods of measurement and sets standards of performance for light output, angle of coverage, ready indication, recycle time and number of flashes for electronic flash equipment of the single flash type, which is primarily intended to prov
20、ide illumination for photography with cameras in which the contacts that control the flash are closed when the shutter of the camera is fully or nearly fully open. 2 References ISO 1229, Photography Expendable photoflash lamps Determination of the light output. ISO 1230, Photography Determination of
21、 flash guide numbers. ISO 3028, Photography Camera flash illuminants Determination of ISO spectral distribution index (ISO/SDI). ISO 5763, Photography Electronic flash equipment Automatic control of exposure. 3 Definitions For the purposes of this International Standard, the definitions given in ISO
22、 1230 and the following definitions apply. 3.1 flash pulse radiation of intense light having inconstant flux, used for photographic purpose 3.2 electronic flash tube a light-transmitting envelope having electrodes and containing a gas through which the energy from a storage capacitor is discharged,
23、thereby producing a flash of light the spectral energy distribution of this light depends on the type of gas and other design factors 3.3 electronic flash equipment an electronic flash tube, usually mounted in a suitable reflector, and the appropriate apparatus for activating and controlling the ele
24、ctronic flash tube 3.4 automatic flash equipment equipment that varies the intensity or duration or both of a flash in such manner as to achieve the necessary exposure of the film independent of the object distance from the flash equipment within given limits (see ISO 5763) 3.5 angle of coverage the
25、 angle between the axis of reflector and the direction where the luminous intensity falls to one half of the value in the axis on symmetrically designed reflectors the angle of coverage is equal to twice the half angle of coverage. For flash equipment producing a pattern which deviates significantly
26、 from a circle, a rectangle within which the luminous intensity does not vary by more than 50 % from the value on axis may be specified by two angles in horizontal and vertical directions of the rectangle. For large flash sources, for example studio flash sources, where the dimensions are not smalle
27、r than 2 m, the method of specifying angle of coverage is not applicable 3.6 light output (for bare flash tubes) the light output measured in two mutually perpendicular equatorial lines around the bare tubes. The cross-line of the planes through the equatorial lines shall be parallel to the optical
28、axis of the lens of the camera 3.7 beam light output the time integral of the luminous intensity of flash equipment in the direction specified by the axis of the reflector, expressed in candela seconds 3.8 stored energy (En) the energy stored in the main capacitor expressed in joules (watt seconds)
29、and determined by the following formula where Cis the capacitance of the combined main capacitor in farads; Uis the peak voltage in volts (see 3.14). 3.9 effective flash duration (t0,5) the time interval from the instant the flash reaches one-half of its peak intensity to the instant it decays to th
30、e same value 3.10 total flash duration (t0,1) the time interval from the instant the flash reaches 10 % of its peak intensity to the instant it decays to the same value En CU2 2 -= Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:44:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 2827:198
31、8 (E) 2 BSI 01-2000 3.11 guide number (GN) see ISO 1230. For flash equipment to which the inverse-square law applies, the guide number is a constant for a given film speed. Guide numbers do not apply to flash equipment or working conditions where the inverse-square law does not apply, which is the c
32、ase when the area or size of the light source is large with respect to the distance between source and object. This condition may exist for very large studio type sources (umbrellas) or in extreme close-up photography. Guide numbers also do not apply to automatic electronic flash equipment when used
33、 in the automatic exposure mode. For studio type equipment to which the inverse-square law does not apply the light output shall be measured at a fixed distance of 2 m and calculated into the corresponding camera lens f-number based on a given film speed 3.12 number of flashes per battery (pertainin
34、g to equipment capable of operation from primary type batteries which are not rechargeable) capacity of the equipment in terms of the total successive flashes, obtainable over a prescribed duty cycle, to an end point the end point is reached when the ready indicator will no longer appear within a 60
35、 s time period NOTEOn equipment capable of changing the energy per flash by use of, for example, a power selector or exposure control system, the operating conditions of the equipment should be fully specified and the number of flashes given for each mode (see clause 6). 3.13 number of flashes per c
36、harge (pertaining to equipment operating from secondary type battery supplies capable of complete recharge after each disabling energy depletion) see 3.12. Additional conditions should be specified such as the initial battery conditioning, the battery charging time and the input power requirements f
37、or the charger unit 3.14 peak voltage the maximum voltage at the energy storage capacitor during a charging cycle when the increase during a 10 s interval is less than 1 % following the procedure outlined in 7.1, the voltage readings are taken at the same time as beam light output is measured 3.15 r
38、egulated voltage (storage capacitor) voltage controlled by a regulating system for equipment with voltage regulating systems operating in its controlling mode, the peak voltage is the minimum voltage to which the regulating system permits the voltage to build during a charge cycle 3.16 ready indicat
39、ion a means, usually visible, of indicating that the equipment is ready to flash 3.17 recycle time the period between release of the flash and subsequent ready indication 3.18 spectral energy distribution see ISO 3028. The spectral energy distribution of the flash radiation should match that of “pho
40、tographic daylight D55” as close as possible in order to achieve a good colour rendition with colour films designated for primary use for daylight illumination spectral energy distribution is expressed as a three number ISO spectral distribution index as described in ISO 3028 (see A.6.1) 4 Test cond
41、itions 4.1 Test arrangement for beam light output and angle of coverage The lamp head of the electronic flash equipment shall be held in a suitable fixture. The fixture shall permit rotation of the lamp head 90 each side, pivoting about the centre of the reflector aperture, or, if no reflector is us
42、ed, about the centre of the bare flash tube with the tube oriented in the position it is normally used with the camera. The fixture shall be calibrated in degrees with an error not exceeding 0,5 and shall hold the flash equipment so that the front cover of the reflector can be correctly adjusted to
43、face the detector of a flash exposure meter. Measurements shall be made in dark, non-reflective surroundings. Other measuring apparatus may be used which permit measurement to the specified tolerances. 4.2 Measuring distances 4.2.1 Distance from flash source to light meter sensor For measurement of
44、the beam light in the manual mode the light meter sensor shall be placed at a distance approximately 2 m in front of the cover of the flash head. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:44:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 2827:1988 (E) BSI 01-20003 4.2.2 Distance f
45、or angle of coverage test The light output measurements for determination of angle of coverage of the flash illumination shall be made at a distance approximately 2 m in front of the cover of the flash head. 4.3 Test apparatus for beam output and flash duration A flash exposure meter measuring incid
46、ent light from the flash equipment may be used to determine beam light output. For determination of the time integral parameters, suitable electronic integration equipment or mechanical integration of the time intensity curve (such as a photograph of an oscilloscope trace) may be employed. The time
47、intensity curve may also be used to determine the flash duration. these instruments shall meet the following conditions: accuracy: 7 % of indicated reading ( 1/10 Ev); spectral response of sensor: shall approximate the luminosity curve of the CIE Standard Observer (photopic response) so that the err
48、or by measuring a light source with a colour temperature between 3 500 K and 7 000 K does not exceed 5 %. See clause A.1 of the Annex. flash duration: shall be capable of measuring time intervals as short as 10 4s (see A.2); general: the instrument shall be linear within the above limits and be able
49、 to measure the high intensities and short durations encountered in this work; sensor size: the sensor shall have a maximum diameter of 50 mm. 4.4 Details and precautions Additional details and precautions for the test are given in clauses A.2 to A.5 of the Annex. 5 Conditioning of flash equipment 5.1 General conditions For each test the equipment under test shall be fully charged and in an operable condition with the storage capacitor formed as specified by the manufacturer. This usually involves operating the equipmen
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