[分享]Rifle scope---Parallax Explained [復(fù)制鏈接]

Whenever rifle scopes are discussed, a topic that frequently arises is parallax. There seems to be a great amount of misunderstanding and confusion concerning this subject. Parallax can be defined appropriately to rifle scopes as; the apparent movement of objects within the field of view in relation to the reticle.

In a telescopic sight, parallax occurs when the “primary image” of the object is formed either in front of, or behind the reticle. If the eye is moved from the optical axis of the scope, this also creates parallax. If the primary image is formed on the same focal plane as the reticle, or if the eye is positioned in the optical axis of the scope, then there is no parallax, regardless of the position of the primary image.

High magnification scopes, or scopes for long range shooting, where even slight sighting errors would be serious, should be equipped with a parallax adjustment. This adjustment of the objective part of the optical system would ensure that the target can be brought in the exact focal plane of the reticle at any distance. Tactical style scopes are not usually supplied with parallax adjustment because the exact range of the target can never be anticipated. Scopes of lower magnification are not usually supplied with parallax adjustment either, because at lower powers the amount of parallax is so small as to have no importance for practical, fast target acquisition.

THERE ARE TWO FACTORS WHICH CAUSE AND DETERMINE THE AMOUNT OF PARALLAX IN A RIFLESCOPE:They are; ](0Vm_es  
1. The distance of the target to the objective-- The objective lens forms a primary image of the subject being viewed and subsequent components invert the image, and there is no parallax. The actual position at which the image is formed is dependent on the distance the target is from the objective. Closer targets are formed farther away from the objective and farther targets are formed closer to the objective. Since the reticle is in a fixed position within the scope housing, the image is not always formed in the same plane as the reticle and, hence parallax. >*}