SIST ISO 516:2022
(Main)Camera shutters — Timing — General definition and mechanical shutter measurements
Camera shutters — Timing — General definition and mechanical shutter measurements
This document provides a uniform basis for determining the exposure times for all types of shutters used in still cameras and contains suitable definitions of the terms used.
It specifies the exposure-time markings for all types of shutters and their tolerances.
The characteristics of all types of mechanical shutters, which are mounted in still cameras and affect the control of exposure, motion-stopping ability and synchronization with a photoflash light source are also defined.
The tolerances specified are the target values for the shutter performance that can be expected to give good results. They are not intended for application as a general inspection standard in controlling the performance of mechanical shutters, since tolerances may vary with the feature and price class of camera tested.
Test methods are described for routine manufacturing testing and quality control. These test methods require access to the focal plane of the camera and can therefore not be applied to assembled digital still cameras.
Obturateurs d'appareils photographiques — Durée d'exposition — Définition générale et mesurages d'obturateur mécanique
Zaklopi na kamerah - Zaklopni časi - Splošna opredelitev in meritve mehanskih zaklopov
Ta dokument ponuja enotno osnovo za določanje časa osvetlitve za vse vrste zaklopov, ki se uporabljajo v fotoaparatih, in vsebuje ustrezne opredelitve uporabljenih izrazov.
Določa oznake za čas osvetlitve za vse vrste zaklopov in njihove tolerance.
Opredeljuje tudi značilnosti vseh vrst mehanskih zaklopov, ki so nameščeni v fotoaparatih in vplivajo na nadzor osvetlitve, sposobnost zaustavljanja gibanja ter sinhronizacijo z bliskavico.
Dovoljena odstopanja so ciljne vrednosti za delovanje zaklopa, od katerega se pričakuje, da bo dal dobre rezultate. Namen ni uporaba kot splošni standard za nadzor delovanja mehanskih zaklopov, saj se odstopanja lahko razlikujejo glede na lastnosti in cenovni razred preskušenih fotoaparatov.
Opisane so preskusne metode za rutinsko preskušanje v proizvodnji in nadzor kakovosti. Te preskusne metode zahtevajo dostop do goriščne ravnine fotoaparata, zato jih ni mogoče uporabiti za sestavljene digitalne fotoaparate.
General Information
Relations
Buy Standard
Standards Content (Sample)
SLOVENSKI STANDARD
SIST ISO 516:2022
01-oktober-2022
Nadomešča:
SIST ISO 516:2011
Zaklopi na kamerah - Zaklopni časi - Splošna opredelitev in meritve mehanskih
zaklopov
Camera shutters — Timing — General definition and mechanical shutter measurements
Obturateurs d'appareils photographiques — Durée d'exposition — Définition générale
et mesurages d'obturateur mécanique
Ta slovenski standard je istoveten z: ISO 516:2019
ICS:
37.040.10 Fotografska oprema. Photographic equipment.
Projektorji Projectors
SIST ISO 516:2022 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST ISO 516:2022
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SIST ISO 516:2022
INTERNATIONAL ISO
STANDARD 516
Fourth edition
2019-04
Camera shutters — Timing — General
definition and mechanical shutter
measurements
Obturateurs d'appareils photographiques — Durée d'exposition —
Définition générale et mesurages d'obturateur mécanique
Reference number
ISO 516:2019(E)
©
ISO 2019
---------------------- Page: 3 ----------------------
SIST ISO 516:2022
ISO 516:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 516:2022
ISO 516:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 4
5 Required characteristics and their tolerances . 5
5.1 Exposure time . 5
5.1.1 Exposure time marking . 6
5.1.2 Tolerances . 6
5.2 Delay time . 6
5.2.1 Front shutters . 6
5.2.2 Focal-plane shutters . 8
6 Test methods . 9
6.1 General . 9
6.2 Apparatus . 9
6.2.1 Apparatus . 9
6.2.2 Detector . 9
6.2.3 Time-interval meter .10
6.3 Front-shutter test .10
6.3.1 Test assembly .10
6.3.2 Procedure .10
6.4 Focal-plane-shutter test .11
6.4.1 Test assembly .11
6.4.2 Procedure .12
7 Explanatory notes .13
7.1 Tolerance .13
7.2 Test method .14
Annex A (normative) Graphic test methods .15
Bibliography .22
© ISO 2019 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 516:2022
ISO 516:2019(E)
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, Part 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, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 42, Photography.
This fourth edition cancels and replaces the third edition (ISO 516:1999) which has been technically
revised. The following changes have been made:
— The title and scope have been updated to reflect that the document is applicable to mechanical
shutters.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 516:2022
ISO 516:2019(E)
Introduction
A superseded edition of this document was developed in the mechanical-shutters-only era. The scope
of this edition has been changed as many digital still cameras with non-mechanical shutters are now
introduced to the market.
© ISO 2019 – All rights reserved v
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SIST ISO 516:2022
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SIST ISO 516:2022
INTERNATIONAL STANDARD ISO 516:2019(E)
Camera shutters — Timing — General definition and
mechanical shutter measurements
1 Scope
This document provides a uniform basis for determining the exposure times for all types of shutters
used in still cameras and contains suitable definitions of the terms used.
It specifies the exposure-time markings for all types of shutters and their tolerances.
The characteristics of all types of mechanical shutters, which are mounted in still cameras and affect
the control of exposure, motion-stopping ability and synchronization with a photoflash light source are
also defined.
The tolerances specified are the target values for the shutter performance that can be expected to
give good results. They are not intended for application as a general inspection standard in controlling
the performance of mechanical shutters, since tolerances may vary with the feature and price class of
camera tested.
Test methods are described for routine manufacturing testing and quality control. These test methods
require access to the focal plane of the camera and can therefore not be applied to assembled digital
still cameras.
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:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
front shutter
any shutter in the vicinity of the lens
Note 1 to entry: The front shutter can be in front of, behind or between the lens elements and can consist of
rotating discs, rotating slats, sliding blades, oscillating blades, etc. Programmed shutters are also included.
Note 2 to entry: The common characteristic for the front shutter is that the entire picture area is exposed almost
simultaneously.
Note 3 to entry: When the shutter and diaphragm are located too far apart, both exposure and shutter speed may
vary at different points in the picture area.
3.2
focal-plane shutter
any shutter in the vicinity of the focal plane
Note 1 to entry: The focal-plane shutter can consist of fixed or variable slit curtains, rotating discs, sliding
blades, etc.
© ISO 2019 – All rights reserved 1
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SIST ISO 516:2022
ISO 516:2019(E)
Note 2 to entry: The essential feature of the focal-plane shutter is that the picture area is exposed incrementally,
in such a way that the time required to expose the entire picture area is greater than the exposure time of any
one point.
3.3
effective time
t
e
best measure of the amount of light falling on the picture area
Note 1 to entry: Effective time is defined by the following formula:
H
t =
e
E
0
Note 2 to entry: At any point on the picture area, t is generally the same for the entire picture area for front
e
shutters when vignetting is not severe. For focal-plane shutters, t will vary with w and v . The formula in Note 1
e c
to entry can be approximated with the below formula for convenience in measurement:
w
t = (focal plane shutter)
e
v
c
The formula in Note 2 to entry can only be applied under the condition of w ≥ d /A.
s
3.4
exposure time
t
eo
effective time measured at the centre of the picture area
3.5
total time
t
o
the time for which any given point in the picture area is exposed to light
Note 1 to entry: At any point on the picture area, to is generally the same, or almost, on the entire picture area for
front shutters.
Note 2 to entry: For a focal-plane shutter, however, to is dependent on w, A, d and V . The curtain displacement to
s c
completely expose one point becomes w + d /A, which can be converted to t , if the velocity is known, using the
s o
following formula:
d
s
w+
A
t =
o
V
c
Note 3 to entry: This formula can be inexact in the presence of vignetting.
See Figure 1.
2 © ISO 2019 – All rights reserved
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SIST ISO 516:2022
ISO 516:2019(E)
a
Taking lens.
b
Curtain.
c
Focal lens.
Figure 1 — Total time for a focal-plane shutter
3.6
shutter efficiency
η
ratio of effective time to total time
Note 1 to entry: The shutter efficiency is given by:
t
e
η=
t
o
3.7
fluctuation of exposure time
p
the value of p is determined by the following formula
x +σ
p
2 =
x −σ
where x and σ are the mean and standard deviation of the values of five successive measurements
3.8
ratio of two adjacent exposure times
q
ratio of the mean values of two adjacent shutter speed settings obtained from values of five successive
measurements
Note 1 to entry: The ratio is expressed by the following formula:
© ISO 2019 – All rights reserved 3
---------------------- Page: 11 ----------------------
SIST ISO 516:2022
ISO 516:2019(E)
tn
()
eo
p
2 =
tn+1
()
eo
Note 2 to entry: t (n) and t (n + 1) are the exposure times of two adjacent shutter speed settings represented
eo eo
by (n) and (n + 1).
3.9
non-uniformity of exposure
r
characteristic which may be found during any single exposure due to lack of coincidence with the
principal plane (front shutter) or to variations in curtain velocity or slit width (focal-plane shutters)
Note 1 to entry: Such non-uniformity is expressed as the ratio of the maximum and minimum effective time
found by exploring the picture area, and is derived from the following formula:
t max
r e
2 =
t min
e
3.10
overall time
T
elapsed time for exposure of all points in the entire picture area
Note 1 to entry: For front shutters, T = t .
o
3.11
photoflash synchronization delay time
t
d
time interval from the initial closing of the shutter synchronization contacts to the moment at which
the shutter element moves to the specified position (see 5.2)
Note 1 to entry: For details of ignition circuits of synchronizers, see ISO 10330.
3.12
X contact
synchronization contact for an electronic flash unit
Note 1 to entry: The contact closes while the shutter is fully opened to enable reception of the reflected light from
the object through the aperture of the lens or for total illumination of the camera aperture. The X contact can
sometimes be used for the M or MF class of photoflash lamp at the slower shutter speeds.
3.13
M contact
synchronization contact for M class of photoflash lamp
3.14
FP contact
synchronization contact for FP class of photoflash lamp
Note 1 to entry: This contact is provided only in the focal plane shutter and can be used for M or MF class of
photoflash lamp at the slower shutter speeds.
4 Symbols
A f-number of the lens
b exposure time error
c tolerance for exposure time
4 © ISO 2019 – All rights reserved
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SIST ISO 516:2022
ISO 516:2019(E)
d tolerance for stop
d distance between focal plane and curtain
s
E maximum illuminance (full open shutter)
o
E exposure value in units
v
e tolerance for exposure meter
f tolerance for film sensitivity
H exposure (time-integral of illuminance)
L film latitude
m magnification factor
n positive or negative integer, or zero
p fluctuation of exposure time, expressed in E
v
q ratio of two adjacent exposure times, expressed in E
v
r non-uniformity of exposure, expressed in E
v
s width of the mask slit in drum tester
T overall time, in seconds (see Figure 3)
t minimum contact duration, in seconds
c
t delay time, in seconds (see Figures 2 and 3)
d
t theoretical exposure time, in seconds [see Formula (1)]
E
t effective time, in seconds (see Figure A.2)
e
t exposure time, in seconds (effective time measured at the centre of the picture area)
eo
t total time, in seconds (see Figure A.2)
o
v average linear velocity of curtain
c
v linear velocity of rotating drum periphery
d
w width of the focal-plane curtain slit
η shutter efficiency
5 Required characteristics and their tolerances
5.1 Exposure time
Theoretical exposure times that form a series are given, in seconds, by the following formula:
1
t = (1)
E
n
2
Shutters shall be designed to provide exposure times selected from the series below, subject to the
tolerances specified in 5.1.2.
© ISO 2019 – All rights reserved 5
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SIST ISO 516:2022
ISO 516:2019(E)
....8,4,2,1,1/2,1/4,1/8,1/16,1/32,1/64,1/128,1/256,1/512,1/1 024,1/2 048...
NOTE 1 Timing of the shutters need be measured at the appropriate aperture of the lens used (see Figures 4
and 5). In the case of cameras that have interchangeable lenses, the standard lens is used for exposure-time
measuring.
NOTE 2 In evaluating shutters without lenses, exposure times are measured under the conditions fixed so as
to be equivalent to the requirements of this document.
NOTE 3 A change in n by one unit needs a change in time by a factor of 2. This unit is called E or a step.
v
5.1.1 Exposure time marking
The exposure-time marking shall be marked as the following rounded-off values of reciprocal numbers
of the series specified in 5.1. Exposure times longer than 1 s shall not, however, be marked as reciprocal
numbers, but should be made evident by colour or some other means of identification.
...8,4,2, 1,2,4,8, 15,30, 60, 125, 250, 500,1 000, 2 000...
The highest marking, however, need not necessarily be selected from this series, but the series
beginning with the next lower number should be selected from this series, whenever practicable, and
progressing as far as is required in the particular application.
5.1.2 Tolerances
The tolerances of exposure time error, fluctuation of exposure times, ratio of two adjacent exposure
times and nonuniformity of exposure should be as shown in Table 1 (see also 7.1). The following
Formula (2), i
...
INTERNATIONAL ISO
STANDARD 516
Fourth edition
2019-04
Camera shutters — Timing — General
definition and mechanical shutter
measurements
Obturateurs d'appareils photographiques — Durée d'exposition —
Définition générale et mesurages d'obturateur mécanique
Reference number
ISO 516:2019(E)
©
ISO 2019
---------------------- Page: 1 ----------------------
ISO 516:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 516:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 4
5 Required characteristics and their tolerances . 5
5.1 Exposure time . 5
5.1.1 Exposure time marking . 6
5.1.2 Tolerances . 6
5.2 Delay time . 6
5.2.1 Front shutters . 6
5.2.2 Focal-plane shutters . 8
6 Test methods . 9
6.1 General . 9
6.2 Apparatus . 9
6.2.1 Apparatus . 9
6.2.2 Detector . 9
6.2.3 Time-interval meter .10
6.3 Front-shutter test .10
6.3.1 Test assembly .10
6.3.2 Procedure .10
6.4 Focal-plane-shutter test .11
6.4.1 Test assembly .11
6.4.2 Procedure .12
7 Explanatory notes .13
7.1 Tolerance .13
7.2 Test method .14
Annex A (normative) Graphic test methods .15
Bibliography .22
© ISO 2019 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 516:2019(E)
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, Part 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, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 42, Photography.
This fourth edition cancels and replaces the third edition (ISO 516:1999) which has been technically
revised. The following changes have been made:
— The title and scope have been updated to reflect that the document is applicable to mechanical
shutters.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 516:2019(E)
Introduction
A superseded edition of this document was developed in the mechanical-shutters-only era. The scope
of this edition has been changed as many digital still cameras with non-mechanical shutters are now
introduced to the market.
© ISO 2019 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 516:2019(E)
Camera shutters — Timing — General definition and
mechanical shutter measurements
1 Scope
This document provides a uniform basis for determining the exposure times for all types of shutters
used in still cameras and contains suitable definitions of the terms used.
It specifies the exposure-time markings for all types of shutters and their tolerances.
The characteristics of all types of mechanical shutters, which are mounted in still cameras and affect
the control of exposure, motion-stopping ability and synchronization with a photoflash light source are
also defined.
The tolerances specified are the target values for the shutter performance that can be expected to
give good results. They are not intended for application as a general inspection standard in controlling
the performance of mechanical shutters, since tolerances may vary with the feature and price class of
camera tested.
Test methods are described for routine manufacturing testing and quality control. These test methods
require access to the focal plane of the camera and can therefore not be applied to assembled digital
still cameras.
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:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
front shutter
any shutter in the vicinity of the lens
Note 1 to entry: The front shutter can be in front of, behind or between the lens elements and can consist of
rotating discs, rotating slats, sliding blades, oscillating blades, etc. Programmed shutters are also included.
Note 2 to entry: The common characteristic for the front shutter is that the entire picture area is exposed almost
simultaneously.
Note 3 to entry: When the shutter and diaphragm are located too far apart, both exposure and shutter speed may
vary at different points in the picture area.
3.2
focal-plane shutter
any shutter in the vicinity of the focal plane
Note 1 to entry: The focal-plane shutter can consist of fixed or variable slit curtains, rotating discs, sliding
blades, etc.
© ISO 2019 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 516:2019(E)
Note 2 to entry: The essential feature of the focal-plane shutter is that the picture area is exposed incrementally,
in such a way that the time required to expose the entire picture area is greater than the exposure time of any
one point.
3.3
effective time
t
e
best measure of the amount of light falling on the picture area
Note 1 to entry: Effective time is defined by the following formula:
H
t =
e
E
0
Note 2 to entry: At any point on the picture area, t is generally the same for the entire picture area for front
e
shutters when vignetting is not severe. For focal-plane shutters, t will vary with w and v . The formula in Note 1
e c
to entry can be approximated with the below formula for convenience in measurement:
w
t = (focal plane shutter)
e
v
c
The formula in Note 2 to entry can only be applied under the condition of w ≥ d /A.
s
3.4
exposure time
t
eo
effective time measured at the centre of the picture area
3.5
total time
t
o
the time for which any given point in the picture area is exposed to light
Note 1 to entry: At any point on the picture area, to is generally the same, or almost, on the entire picture area for
front shutters.
Note 2 to entry: For a focal-plane shutter, however, to is dependent on w, A, d and V . The curtain displacement to
s c
completely expose one point becomes w + d /A, which can be converted to t , if the velocity is known, using the
s o
following formula:
d
s
w+
A
t =
o
V
c
Note 3 to entry: This formula can be inexact in the presence of vignetting.
See Figure 1.
2 © ISO 2019 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 516:2019(E)
a
Taking lens.
b
Curtain.
c
Focal lens.
Figure 1 — Total time for a focal-plane shutter
3.6
shutter efficiency
η
ratio of effective time to total time
Note 1 to entry: The shutter efficiency is given by:
t
e
η=
t
o
3.7
fluctuation of exposure time
p
the value of p is determined by the following formula
x +σ
p
2 =
x −σ
where x and σ are the mean and standard deviation of the values of five successive measurements
3.8
ratio of two adjacent exposure times
q
ratio of the mean values of two adjacent shutter speed settings obtained from values of five successive
measurements
Note 1 to entry: The ratio is expressed by the following formula:
© ISO 2019 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO 516:2019(E)
tn
()
eo
p
2 =
tn+1
()
eo
Note 2 to entry: t (n) and t (n + 1) are the exposure times of two adjacent shutter speed settings represented
eo eo
by (n) and (n + 1).
3.9
non-uniformity of exposure
r
characteristic which may be found during any single exposure due to lack of coincidence with the
principal plane (front shutter) or to variations in curtain velocity or slit width (focal-plane shutters)
Note 1 to entry: Such non-uniformity is expressed as the ratio of the maximum and minimum effective time
found by exploring the picture area, and is derived from the following formula:
t max
r e
2 =
t min
e
3.10
overall time
T
elapsed time for exposure of all points in the entire picture area
Note 1 to entry: For front shutters, T = t .
o
3.11
photoflash synchronization delay time
t
d
time interval from the initial closing of the shutter synchronization contacts to the moment at which
the shutter element moves to the specified position (see 5.2)
Note 1 to entry: For details of ignition circuits of synchronizers, see ISO 10330.
3.12
X contact
synchronization contact for an electronic flash unit
Note 1 to entry: The contact closes while the shutter is fully opened to enable reception of the reflected light from
the object through the aperture of the lens or for total illumination of the camera aperture. The X contact can
sometimes be used for the M or MF class of photoflash lamp at the slower shutter speeds.
3.13
M contact
synchronization contact for M class of photoflash lamp
3.14
FP contact
synchronization contact for FP class of photoflash lamp
Note 1 to entry: This contact is provided only in the focal plane shutter and can be used for M or MF class of
photoflash lamp at the slower shutter speeds.
4 Symbols
A f-number of the lens
b exposure time error
c tolerance for exposure time
4 © ISO 2019 – All rights reserved
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ISO 516:2019(E)
d tolerance for stop
d distance between focal plane and curtain
s
E maximum illuminance (full open shutter)
o
E exposure value in units
v
e tolerance for exposure meter
f tolerance for film sensitivity
H exposure (time-integral of illuminance)
L film latitude
m magnification factor
n positive or negative integer, or zero
p fluctuation of exposure time, expressed in E
v
q ratio of two adjacent exposure times, expressed in E
v
r non-uniformity of exposure, expressed in E
v
s width of the mask slit in drum tester
T overall time, in seconds (see Figure 3)
t minimum contact duration, in seconds
c
t delay time, in seconds (see Figures 2 and 3)
d
t theoretical exposure time, in seconds [see Formula (1)]
E
t effective time, in seconds (see Figure A.2)
e
t exposure time, in seconds (effective time measured at the centre of the picture area)
eo
t total time, in seconds (see Figure A.2)
o
v average linear velocity of curtain
c
v linear velocity of rotating drum periphery
d
w width of the focal-plane curtain slit
η shutter efficiency
5 Required characteristics and their tolerances
5.1 Exposure time
Theoretical exposure times that form a series are given, in seconds, by the following formula:
1
t = (1)
E
n
2
Shutters shall be designed to provide exposure times selected from the series below, subject to the
tolerances specified in 5.1.2.
© ISO 2019 – All rights reserved 5
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ISO 516:2019(E)
....8,4,2,1,1/2,1/4,1/8,1/16,1/32,1/64,1/128,1/256,1/512,1/1 024,1/2 048...
NOTE 1 Timing of the shutters need be measured at the appropriate aperture of the lens used (see Figures 4
and 5). In the case of cameras that have interchangeable lenses, the standard lens is used for exposure-time
measuring.
NOTE 2 In evaluating shutters without lenses, exposure times are measured under the conditions fixed so as
to be equivalent to the requirements of this document.
NOTE 3 A change in n by one unit needs a change in time by a factor of 2. This unit is called E or a step.
v
5.1.1 Exposure time marking
The exposure-time marking shall be marked as the following rounded-off values of reciprocal numbers
of the series specified in 5.1. Exposure times longer than 1 s shall not, however, be marked as reciprocal
numbers, but should be made evident by colour or some other means of identification.
...8,4,2, 1,2,4,8, 15,30, 60, 125, 250, 500,1 000, 2 000...
The highest marking, however, need not necessarily be selected from this series, but the series
beginning with the next lower number should be selected from this series, whenever practicable, and
progressing as far as is required in the particular application.
5.1.2 Tolerances
The tolerances of exposure time error, fluctuation of exposure times, ratio of two adjacent exposure
times and nonuniformity of exposure should be as shown in Table 1 (see also 7.1). The following
Formula (2), in seconds, is applicable to the tolerance of the exposure time:
1
t = (2)
eo
()nb+
2
Table 1 — Tolerances for b, p, q and r
Unit: E
v
Quantity
Exposure time
a
b p q r
1/125 and longer ±0,3 ≤0,3 1 ± 0,45 ≤0,2
shorter than 1/125 ±0,45 ≤0,45 1 ± 0,65 ≤0,6
a
The admissible values for individual exposure times are calculated and tabulated in Annex A.
Over the range of −10 °C to 40 °C, the tolerances specified in Table 1 should not be exceeded, with the
e
...
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