ASTM F1753-96 PDF

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.