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Rifles, Reloading, Optics, Equipment
Long Range Scopes and Other Optics
first vs. second focal plane, could there be another option?
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<blockquote data-quote="LouBoyd" data-source="post: 986771" data-attributes="member: 9253"><p>Nearly all electronic night vision scopes whether they have image intensiifiers, CCDs, or thermal arrays have two focal planes, but they behave differently from an all optical scope. In any of those devices having either the first or second focal plane our of focus does make the image of the target or reticle fuzzy and reduces resolution but unlike optical scopes they do not introduce parallax error with respect to eye position behind the scope. </p><p></p><p>Night vision scope which use an intensifier in front or behind a conventional scope can have three or more focal planes, but they will still eliminate the parallax effects of eye placement. </p><p></p><p>It is also possible for the reticle to be projected onto the target directly as with a laser pointer. that is essentially a zero focal plane reticle. If magnification is needed a conventional riflescope can be used and it will have two focal planes but neither needs to have a reticle. By using a Galelian type telescope there is no focal plane within the riflescope itself The only images of the reticle are on the target and on the retina of the eye. Galilean telescopes are rarely used for riflescopes since they have no focal plane where a reticle can be placed. Riflescopes usually have two focal planes but can use a prism assembly to give an erect image and only have one focal plane. Variable magnification optics can be placed before or after that focal plane giving similar perfomance to a first or second focal plane conventional scope. </p><p></p><p>A fixed power conventional riflescope can have it's reticle at the first or second focal plane although there is little difference in their performance. either way they still need separate adjustments on both sides of the riticle for parallax and the diopter correction.</p></blockquote><p></p>
[QUOTE="LouBoyd, post: 986771, member: 9253"] Nearly all electronic night vision scopes whether they have image intensiifiers, CCDs, or thermal arrays have two focal planes, but they behave differently from an all optical scope. In any of those devices having either the first or second focal plane our of focus does make the image of the target or reticle fuzzy and reduces resolution but unlike optical scopes they do not introduce parallax error with respect to eye position behind the scope. Night vision scope which use an intensifier in front or behind a conventional scope can have three or more focal planes, but they will still eliminate the parallax effects of eye placement. It is also possible for the reticle to be projected onto the target directly as with a laser pointer. that is essentially a zero focal plane reticle. If magnification is needed a conventional riflescope can be used and it will have two focal planes but neither needs to have a reticle. By using a Galelian type telescope there is no focal plane within the riflescope itself The only images of the reticle are on the target and on the retina of the eye. Galilean telescopes are rarely used for riflescopes since they have no focal plane where a reticle can be placed. Riflescopes usually have two focal planes but can use a prism assembly to give an erect image and only have one focal plane. Variable magnification optics can be placed before or after that focal plane giving similar perfomance to a first or second focal plane conventional scope. A fixed power conventional riflescope can have it's reticle at the first or second focal plane although there is little difference in their performance. either way they still need separate adjustments on both sides of the riticle for parallax and the diopter correction. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Long Range Scopes and Other Optics
first vs. second focal plane, could there be another option?
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