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Hunting
Long Range Hunting & Shooting
scope size 40 mm vs 50mm
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<blockquote data-quote="Greyfox" data-source="post: 1483192" data-attributes="member: 10291"><p>IMO, it's also unfair to coompare a 40mm to a 50mm scope....at least in a technical sense. If you back to the basic question from the OP, perhaps it's best to give the basic explanation of the difference. Assuming that glass quality and magnification setting is "equal", the larger the objective, the greater the size of the exit pupil, and the light delivered to the eye. At 10x, a 40mm scopes exit pupil will be <strong>4mm</strong>(40 divided by 10). A 50mm will be <strong>5mm, </strong>a 20% increase in light delivered to the eye. It's important to note that the size of a human pupil expands to 5-7mm. Any addition light produced by larger exit pupils from the scope will not be accepted by the eye. In the above comparison a 50mm will provide the eye with more light gathering ability and very likely be noticeable in low light conditions. As a side note, the eye box in this example will be larger as well. At higher powers at longer ranges in low light, the difference in light gathering can be more dramatic. At 15x, the exit pupil of a 40mm will be 2.7mm, the 56mm will be 3.7mm, almost 40% greater light gathering ability that the eye(5-7mm) can take advantage of. Of course, other factors can come into play such as glass quality, cost,construction, size, weight, etc, which results in the shooter making trade-offs. All things being equal, within the boundaries of the human eye, a larger objective lens will gather more light. Apologies for the long winded explanation.</p></blockquote><p></p>
[QUOTE="Greyfox, post: 1483192, member: 10291"] IMO, it’s also unfair to coompare a 40mm to a 50mm scope....at least in a technical sense. If you back to the basic question from the OP, perhaps it’s best to give the basic explanation of the difference. Assuming that glass quality and magnification setting is “equal”, the larger the objective, the greater the size of the exit pupil, and the light delivered to the eye. At 10x, a 40mm scopes exit pupil will be [B]4mm[/B](40 divided by 10). A 50mm will be [B]5mm, [/B]a 20% increase in light delivered to the eye. It’s important to note that the size of a human pupil expands to 5-7mm. Any addition light produced by larger exit pupils from the scope will not be accepted by the eye. In the above comparison a 50mm will provide the eye with more light gathering ability and very likely be noticeable in low light conditions. As a side note, the eye box in this example will be larger as well. At higher powers at longer ranges in low light, the difference in light gathering can be more dramatic. At 15x, the exit pupil of a 40mm will be 2.7mm, the 56mm will be 3.7mm, almost 40% greater light gathering ability that the eye(5-7mm) can take advantage of. Of course, other factors can come into play such as glass quality, cost,construction, size, weight, etc, which results in the shooter making trade-offs. All things being equal, within the boundaries of the human eye, a larger objective lens will gather more light. Apologies for the long winded explanation. [/QUOTE]
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Long Range Hunting & Shooting
scope size 40 mm vs 50mm
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