1、Designation: F1753 96 (Reapproved 2014) An American National StandardStandard Specification forClassification and Marking of Single-Lens Scopes for Usewith Archery Bows1This standard is issued under the fixed designation F1753; the number immediately following the designation indicates the year ofor
2、iginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers lenses and scopes used inconjunctio
3、n with archery bows. It establishes a standardizedsystem for the classification of these lenses in terms of theiroptical magnification, the marking of the scopes in which thelenses are mounted, and charts depicting the empirical rela-tionship of the apparent magnification the consumer can expectto o
4、btain when a correctly marked lens is used under specificconditions.1.2 AcuityThe visual acuity of these lenses is related tothe magnification of the lens in general. For the average subjectthere can be an improvement in acuity with lenses havingapparent magnifications of 2 to 4 and a decrement in a
5、cuitywith lenses of 6 and greater.1.2.1 Acuity also is dependent on other factors, such as thespecific individual, lens quality, and the size and quality of therear aperture (peep) used in conjunction with the lens. Beyondthis statement, acuity is not the subject of this specification.1.3 The values
6、 stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.2. Terminology2.1 Definitions:2.1.1 apparent magnification, napparent increase in sizeof an object as viewed through the subject lens held at aspecific distance from the users eye.2.1.2 diop
7、ter, nreciprocal of the focal length of the lens asmeasured in metres. One diopter is the rating obtained whenthe constant 1 is divided by the focal length value of a lenshaving a 1-m focal length.2.1.3 eye-to-scope distance (ETS), ndistance the (scope)lens is placed from the individuals eye when in
8、 use. If theeye-to-scope distance is measured in metres, it is specified as(ESM) and no conversion factor is required in the apparentmagnification formula. When the eye-to-scope distance ismeasured in inches, it is designated as (ESI). To calculateapparent magnification, the metres-to-inches convers
9、ion factorof 39.37 appears in the equation.2.1.4 focal length, ndistance, measured in metres, fromthe center of the subject lens to the point where incident planelight waves passing through the lens are brought to the sharpestpossible focus.2.1.5 optical magnification, ncharacteristic of a particula
10、rlens defined as the reciprocal of the lens focal length asmeasured in metres and stated in diopters.2.1.6 peep sight, nrear sighting device placed in or ontothe bow string, having a small opening in it that the archerpeers through to view the lens or scope being used as a sightingdevice. The combin
11、ation of the lens and rear peep sight used inthis manner mimics a primitive telescope.3. Classification3.1 Optical MagnificationThis is the magnifying power ofa lens as measured by the reciprocal of the focal length of thelens in metres. It is expressed as a practical unit in terms of afocal length
12、equal to one metre (the unit diopter).The larger thediopter number, the greater the magnifying power of the lens.3.2 Apparent MagnificationThis is the apparent increasein object size one experiences when viewing the object throughone of these magnifying lenses. It is dependent on thefollowing two fa
13、ctors:3.2.1 The optical magnification of the scope lens as mea-sured in diopters, and3.2.2 The distance the scope is placed from the users eye.3.3 Apparent magnification is defined empirically by thefollowing relationship:Apparent magnification 5 1/1 2 D 3 ESM! (1)where:D = lens optical magnificatio
14、n, diopters, andESM = eye-to-scope distance, m.3.3.1 If the eye-to-scope distance is measured in inches(ESI), the relationship becomes:Apparent magnification 5 1/1 2 D 3 ESI/39.37! (2)1This specification is under the jurisdiction of ASTM Committee F08 on SportsEquipment, Playing Surfaces, and Facili
15、ties and is the direct responsibility ofSubcommittee F08.16 on Archery Products.Current edition approved Sept. 1, 2014. Published November 2014. Originallyapproved in 1996. Last previous edition approved in 2010 as F1753 96 (2010).DOI: 10.1520/F1753-96R14.Copyright ASTM International, 100 Barr Harbo
16、r Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1where:ESI = eye-to-scope distance, in., and39.37 = metres-to-inches conversion factor.3.4 Fig. 1 and Fig. 2 are graphic representations of themagnification relationship. Individually, one might prefer onechart over the other. Both
17、 charts contain the same informationbut display that information in a different format.3.4.1 Given the optical magnification of a lens in dioptersand the distance it is to be placed from the users eye, one candetermine the apparent magnification, that is, 2, 3, 4, etc.NOTE 1Fig. 3 and Fig. 4 are sim
18、ply the metric versions of the chartsin Fig. 1 and Fig. 2.3.5 Classification ToleranceThe classification of lensesused in archery scopes shall be determined by measurement oftheir focal length in metres. These lenses shall be specified asa given diopter and will conform to that classification byhavi
19、ng a focal length that corresponds to that diopter valuewithin 63%.4. Significance and Use4.1 This specification is intended to ensure uniform classi-fication of the lenses and the marking of scopes to avoidconfusion of the consumer, which results form the use ofdifferent classification and identifi
20、cation systems.4.2 This specification is based on the use of the diopter thatis the reciprocal of the focal length of the lens as measured inmetres.5. Product Marking5.1 Scopes for use on archery bows shall be marked clearlyand permanently with the diopter number of the lens used inthat scope.6. Key
21、words6.1 archery lenses; diopter; focal length; magnifying sights;scopesFIG. 1 Apparent Magnification of Single-Lens ScopesF1753 96 (2014)2FIG. 2 Apparent Magnification of Single-Lens ScopesFIG. 3 Apparent Magnification of Single-Lens ScopesF1753 96 (2014)3RATIONALEA number of manufacturers of lense
22、s and scopes used in archery recognized the need for uniformity in specifying the mag-nifying power of single-lens bow scopes and contacted Subcommittee F08.16 for assistance. Various lenses were obtained,tests were done to determine the actual and apparent magnification, and mathematical relationsh
23、ips were developed leading tothe establishment of this specification.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of an
24、y such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are i
25、nvited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not receiv
26、ed a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of
27、this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 4 Apparent Magnification of Single-Lens ScopesF1753 96 (2014)4
