Toggle user menu
Toggle menu
ISO/DIS 14135
ISO/DIS 14135
ISO/DIS 14135: Optics and photonics — Specifications for telescopic sights — General-purpose scopes and high-performance sights

ISO/DIS 14135

ISO/TC 172/SC 4

Secretariat: DIN

Date: 2025-12-22

Optics and photonics — Specifications for telescopic sights — General-purpose scopes and high-performance sights

Optique et photonique — Spécifications pour lunettes de pointage — Lunettes d'usage général et lunettes haute performance

DIS stage

© ISO 2025

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

E-mail: copyright@iso.org

Website: www.iso.org

Published in Switzerland

Contents

Foreword

Scope

Normative references

Terms and definitions

Classification

Interfaces

Specification requirements

Consumer information

Marking

Information brochure

Conformity

(informative) Recommended interface dimensions

Bibliography

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 document 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).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO [had/had not] received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents.ISO shall not be held responsible for identifying any or all such patent rights.

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 ISO/TC 172, Optics and photonics, Subcommittee SC 4, Telescopic systems.

This fifth edition cancels and replaces the fourth edition (ISO 14135-1:2021) and the fourth edition (ISO 14135-2:2021), which has been technically revised.

The main changes are as follows:

  • the title has been changed.
  • the technical content from both standards has been combined into one document.
  • some minimum requirements for optical charateristics have been changed.

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.

Optics and photonics — Specifications for telescopic sights — General-purpose scopes and high-performance sights

1.0 Scope

This document applies to general-purpose and high-performance telescopic sights, used on firearms and airguns. It contains a classification of the usage of telescopic sights and specifies interfaces, minimum requirements and tolerances to their performances.

2.0 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 14490-1, Optics and optical instruments — Test methods for telescopic systems — Part 1: Test methods for basic characteristics

ISO 14490-3, Optics and photonics — Test methods for telescopic systems — Part 3: Test methods for telescopic sights

ISO 14490-5, Optics and photonics — Test methods for telescopic systems — Part 5: Test methods for transmittance

ISO 14490-7, Optics and photonics — Test methods for telescopic systems — Part 7: Test methods for limit of resolution

ISO 20711, Optics and photonics — Environmental requirements — Test requirements for telescopic systems

3.0 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 14132-1 and ISO 14132-3 apply.

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

4.0 Classification

Due to different requirements, telescopic sights shall be classified according to their end use, thus:

  • telescopic sights for airguns;
  • telescopic sights for pistols (e.g. handgun scopes);
  • telescopic sights for rifles (e.g. hunting telescopic sights, competition telescopic sights).

Furthermore, telescopic sights are classified into general-purpose and high-performance sights based on their characteristics.

5.0 Interfaces

Telescopic sights shall have interfaces to mounting systems for interconnection with firearms.

The interface areas shall be the central tube and, if of different size, the objective tube.

The interface areas shall be cylindrical in shape. Alternatively, the central tube may have a dovetail at the bottom side.

Recommended interface dimensions are given in Annex A.

For interface areas, see Figure 1.

a) Figure 1a

b) Figure 1b

Key

1 objective tube

2 central tube

3 Interface area e.g. dovetail or rail (optional)

Dc diamenter of central tube

Do diamenter of objective tube

Figure 1 — Interface areas (schematic)

6.0 Specification requirements

Specification requirements are defined by tolerances or minimum requirements for the important characteristics of telescopic sights.

Tolerances specify maximum deviations between measured and nominal values. Nominal values shall be laid down by the manufacturing or trading company.

Telescopic sights shall conform to the environmental requirements relative to the respective sight type, as appropriate. These environmental requirements shall be specified in accordance ISO 20711.

Conformity of the telescopic sight with the requirements given in Table 1 and Table 2 shall be tested according to the test methods specified in ISO 14490-1, ISO 14490-3, ISO 14490-5 and ISO 14490-7.

Table 1 — Acceptable deviations of optical characteristics

Characteristics

Type of telescopic sight

Maximal deviation

General-purpose telescopic sight

High-performance telescope sight

Magnification

Γ ≤ 3

Γ > 3

Zoom

Γ ≤ 3

Γ > 3

Zoom

All

±10 %

±5 %

±10 %

±5 %

±3 %

±5 %

Field of view

±5 %

±5 %

±3 %

±5 %

Entrance pupil diametera

For airguns

±5 %

±5 %

For rifles or pistols

±3 %

±3 %

Zero setting of dioptre scaleb, in dioptres (dpt)

Γ ≤ 2

Γ >2

Γ ≤ 2

Γ >2

All

Not required

± 0,5 %

Not required

± 0,25 %

Parallax of reticlec, in min of arc

Γ < 6

Γ ≥ 6

Γ < 6

Γ ≥ 6

For airguns

6/Γ

Not required

4/Γ

Not required

For pistols

4,5/Γ

Not required

3/Γ

Not required

For rifles

3/Γ

0,5

2/Γ

0,3

Centre of reticled, in relation to total field of view

For airguns

± 1,5 %

± 1,0 %

For rifles or pistols

± 1,5 %

± 0,7 %

Reticle tilt, in degrees

all

± 2

± 2

Reticle tracking, in degrees

For rifles or pistols

± 2

± 2

Line of sight shift due to zoomingc, in min of arc

Reticle in 1st image plane

Not applicable

Not applicable

Γ≤2

2<Γ≤6

Γ>6

Γ≤2

2< Γ≤6

Γ > 6

Reticle in 2nd image plane e

3

6/Γ

1

1,5

3/Γ

0,5

a At maximum magnification on zoom-telescopic sights.

b This tolerance includes focus shift due to zooming.

c Angular deviation in object space.

d In relation to centre of field of view.

e Γ is the minimum magnification of the zoom system.

Table 2 — Minimum requirements for optical characteristics

Characteristics

Type of telescopic sight

Minimum value/requirement

General-purpose telescopic sight

High-performance telescopic sight

Eye relief, in millimetres

For airguns

50

50

For pistols

250

250

For rifles, with no prismatic inverter

70

70

For rifles, with a prismatic inverter

55

70

Resolution for centre of the field, in arc seconds (exit pupil ≤4,5 mm)

All

≤400/Da

≤300/Da

Resolution for centre of the field, in arc seconds (exit pupil >4,5 mm)

For airguns

≤2 × 60/Γb

≤2 × 60/Γb

For pistols

≤1,5 × 60/Γ

≤1,2 × 60/Γ

For rifles

≤1,5 × 60/Γ

≤1,0 × 60/Γ

Dioptre adjustment range (total), in dioptres (dpt)

For pistols or rifles

4 (including the range -2 to +2)

6 (including the range -2 to +2)

Total reticle adjustment rangec, in min of arc

For rifles or pistols

30

50

a D is the entrance pupil diameter, in millimetres, in accordance with ISO 14132-1.

b Γ is the magnification in accordance with ISO 14132-1.

c Independent for both elevation and windage adjustment.

Anti-reflective coatings shall be used on all polished optical surfaces with the exception of reticles and filters.

7.0 Consumer information

7.1 Marking

For identification and operation, telescopic sights shall have, as a minimum, the markings listed in Table 3.

Table 3 — Designation and marking

Characteristics

Marking

Required

Recommended

Magnification or range of magnificationa

×

Entrance pupil diametera

×

Name of manufacturer or registered trademark

×

Product name or identification

×

Country of origin

×

Serial number

×

Position for zero dioptre

×

Value of reticle adjustment per click

×

Direction of adjustment for point of impact

×

a Basic designation is given by the combination of magnification and diameter of entrance pupil, e.g. 6 × 42 or 3 − 10 × 50.

7.1.1 Information brochure

Product catalogues, user manuals and other technical information brochures for telescopic sights shall provide complete information at least on the technical characteristics specified in Table 4

7.1.2 Conformity

Products according to the requirements given in this document can be designated as “General-purpose sights in accordance with ISO 14135 ”or “High-performance sights in accordance with ISO 14135.”

Table 4 — Information for the product

Characteristics

Information

Required

Recommended

Magnification or range of magnification

×

Entrance pupil diameter, in mm

×

Name of manufacturer or registered trademark

×

Product name or identification

×

Country of origin

×

Field of view, in m/100 m or ft/100 yd or degree

×

Exit pupil diameter, in mm

×

Resolution or MTF

×

Light transmission

×

Type of coating

×

Twilight number

×

Eye relief range, in mm

×

Eye relief , in mm

×

Critical eye relief, in mm

×

Dimension/subtense of reticles

×

Parallax-free distance, in m or yd

×

Total reticle adjustment range

×

Value of reticle adjustment per click

High- performance

General-purpose

Direction of adjustment for point of impact

×

Mechanical dimensions, in mm

×

Mass

×

Operational temperature range

×

Storage temperature range

×

Water tightness

×


  1. (informative)

    Recommended interface dimensions

For recommended interface dimensions, see Table A.1. For example of a central tube with inside dovetail and adapter (cross section), see Figure A.2 For example of a sliding block, see Figure A.3. For example of a rail mount, see Figure A.4.

Table A.1 — Recommendended interface dimensions

Shape

Dimensiona

Tolerance

Application

Dc

Do

Cylindrical

19 mm or 22 mm

All

±0,1 mm

For airguns

Cylindrical

25,4 mm (1 in), 26 mm, 30 mm, 34 mm;

for Dc > 34 mm every integer value in mm

25,4 mm (1 in), 26 mm, 30 mm, 34 mm;

for Do > 34 mm every integer value in mm

±0,1 mm

For handguns

Cylindrical

25,4 mm (1 in), 26 mm, 30 mm, 34 mm;

for Dc > 34 mm every integer value in mm

25,4 mm (1 in), 26 mm, 30 mm, 36 mm;

for Do > 36 mm every integer value in mm

±0,1 mm

For rifles

With dovetail (see Figure A.1)

Manufacturer’s specification

1 in, 26 mm, 30 mm, 36 mm;

for Do > 36 mm every integer value in mm

±0,1 mm

For rifles

a Dc is the central tube diameter; Do is the objective tube diameter (see Figure 1).

a) Cut through the tube at the turret position

b) Cut through the tube between objective and turret position

Figure A.1 — Example of central tube with dovetail (cross section)

a) Cut through the tube at the turret position

b) Cut through the tube between objective and turret position

Figure A.2 — Example of central tube with inside dovetail and adapter (cross section)

Key

a Theoretical measure for the shape without beve

Area face milling

Figure A.3 — Example of a sliding block

Key

Area face milling

Figure A.4 — Example of a rail mount

Bibliography

[1] ISO 14132-1, Optics and photonics — Vocabulary for telescopic systems — Part 1: General terms and alphabetical indexes of terms in ISO 14132

[2] ISO 14132-3, Optics and photonics — Vocabulary for telescopic systems — Part 3: Terms for telescopic sights

espa-banner