ASTM F1753-96

Standard Specification for Classification and Marking of Single-Lens Scopes for Use with Archery Bows

SCOPE
1.1 This specification covers lenses and scopes used in conjunction with archery bows. It establishes a standardized system for the classification of these lenses in terms of their optical magnification, the marking of the scopes in which the lenses are mounted, and charts depicting the empirical relationship of the apparent magnification the consumer can expect to obtain when a correctly marked lens is used under specific conditions.
1.2 Acuity—The visual acuity of these lenses is related to the magnification of the lens in general. For the average subject there can be an improvement in acuity with lenses having apparent magnifications of 2 to 4X and a decrement in acuity with lenses of 6X and greater.
1.2.1 Acuity also is dependent on other factors, such as the specific individual, lens quality, and the size and quality of the rear aperture (peep) used in conjunction with the lens. Beyond this statement, acuity is not the subject of this specification.

General Information

• Status: Historical
• Publication Date: 09-Nov-1996
• Technical Committee: F08 - Sports Equipment, Playing Surfaces, and Facilities
• Drafting Committee: F08.16 - Archery Products

Relations

• Replaced By: ASTM F1753-96(2001) - Standard Specification for Classification and Marking of Single-Lens Scopes for Use with Archery Bows
• Effective Date: 10-Nov-1996

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: F 1753 – 96
Standard Specification for
Classification and Marking of Single-Lens Scopes for Use
with Archery Bows
This standard is issued under the fixed designation F 1753; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope plane light waves passing through the lens are brought to the
sharpest possible focus.
1.1 This specification covers lenses and scopes used in
2.1.5 optical magnification, n—the characteristic of a par-
conjunction with archery bows. It establishes a standardized
ticular lens defined as the reciprocal of the lens focal length as
system for the classification of these lenses in terms of their
measured in metres and stated in diopters.
optical magnification, the marking of the scopes in which the
2.1.6 peep sight, n—a rear sighting device placed in or onto
lenses are mounted, and charts depicting the empirical rela-
the bow string, having a small opening in it that the archer
tionship of the apparent magnification the consumer can expect
peers through to view the lens or scope being used as a sighting
to obtain when a correctly marked lens is used under specific
device. The combination of the lens and rear peep sight used in
conditions.
this manner mimics a primitive telescope.
1.2 Acuity—The visual acuity of these lenses is related to
the magnification of the lens in general. For the average subject
3. Classification
there can be an improvement in acuity with lenses having
3.1 Optical Magnification—This is the magnifying power
apparent magnifications of 2 to 43 and a decrement in acuity
of a lens as measured by the reciprocal of the focal length of
with lenses of 63 and greater.
the lens in metres. It is expressed as a practical unit in terms of
1.2.1 Acuity also is dependent on other factors, such as the
a focal length equal to one metre (the unit diopter). The larger
specific individual, lens quality, and the size and quality of the
the diopter number, the greater the magnifying power of the
rear aperture (peep) used in conjunction with the lens. Beyond
lens.
this statement, acuity is not the subject of this specification.
3.2 Apparent Magnification—This is the apparent increase
2. Terminology in object size one experiences when viewing the object through
one of these magnifying lenses. It is dependent on the
2.1 Definitions:
following two factors:
2.1.1 apparent magnification, n—the apparent increase in
3.2.1 The optical magnification of the scope lens as mea-
size of an object as viewed through the subject lens held at a
sured in diopters, and
specific distance from the user’s eye.
3.2.2 The distance the scope is placed from the user’s eye.
2.1.2 diopter, n—the reciprocal of the focal length of the
3.3 Apparent magnification is defined empirically by the
lens as measured in metres. One diopter is the rating obtained
following relationship:
when the constant 1 is divided by the focal length value of a
lens having a 1-m focal length.
Apparent magnification 5 1/~1 2 D 3 ESM! (1)
2.1.3 eye-to-scope distance (ETS), n—the distance the
where:
(scope) lens is placed from the individual’s eye when in use. If
D 5 lens optical magnification, diopters, and
the eye-to-scope distance is measured in metres, it is specified
ESM 5 eye-to-scope distance, m.
as (ESM) and no conversion factor is required in the apparent
3.3.1 If the eye-to-scope distance is measured in inches
magnification formula. When the eye-to-scope distance is
(ESI), the relationship becomes:
measured in inches, it is designated as (ESI). To calculate
Apparent magnification 5 1/~1 2 D 3 ESI/39.37! (2)
apparent magnification, the metres-to-inches conversion factor
of 39.37 appears in the equation.
where:
2.1.4 focal length, n—the distance, measured in metres,
ESI 5 eye-t
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