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Rifles, Reloading, Optics, Equipment
Long Range Scopes and Other Optics
High magnification range - advantages/disadvantages?
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<blockquote data-quote="bruce_ventura" data-source="post: 775224" data-attributes="member: 34084"><p>Another possible drawback to high zoom ratio is high glare and low contrast. Generally speaking, the higher the magnification, the higher the glare. which reduces contrast. Also, glare tends to be highest near just the edge of the exit pupil. In scopes that have noticeable glare, the glare tends to be bad when the exit pupil is smaller than the eye pupil. On these scopes the extra magnification may not be useful in high glare conditions, such as when facing the afternoon sun and looking into shaded areas, or on overcast days in general. </p><p></p><p>Also, I have a nit about some manufacturers who claim that their scopes have higher magnification ratio than they really have. Some of these wide ratio scopes don't actually give you a wide ratio in the field of view. Instead, the field of view stops increasing at some point before the minimum zoom value is reached. As the zoom is decreased further, the entire sight picture starts to decrease. The magnification decreases, but the field of view stays constant. It appears as though the scope is being pulled away from your eye. </p><p></p><p>For a hunting scope, the primary motivation for turning the zoom down is to see more of the target area. A wider field of view speeds up target acquisition and provides better situational awareness. If the scope doesn't increase the field of view, then reducing the magnification isn't very useful to me. As far as I'm concerned, the lower end of the range is that magnification at which the field of view stops increasing.</p><p></p><p>Here are three examples: On the S&B 5-25x50, the field of view stops increasing below 7X. In my book that makes it really 3.6:1 zoom ratio, not 5:1. On the US Optics LR-17 3.5-17x50 it happens below 6X, making it really 2.8:1 zoom ratio, not 4.9:1, On the Bushnell HDMR 3.2-21x50 it happens below about 4.5X, making it really 4.7:1 zoom ratio, not 6.6:1. </p><p></p><p>Still, there is one thing in their favor. Another reason to reduce the magnification is to increase brightness in low light conditions by increasing the exit pupil. Fortunately, on the all wide ratio scopes I've inspected, the exit pupil does increase all they way to lowest magnification. </p><p></p><p>Not all wide ratio scopes have this problem. The Swarovski Z5 and Z6 scopes I've looked at increase the field of view all the way down to the lowest magnification.</p></blockquote><p></p>
[QUOTE="bruce_ventura, post: 775224, member: 34084"] Another possible drawback to high zoom ratio is high glare and low contrast. Generally speaking, the higher the magnification, the higher the glare. which reduces contrast. Also, glare tends to be highest near just the edge of the exit pupil. In scopes that have noticeable glare, the glare tends to be bad when the exit pupil is smaller than the eye pupil. On these scopes the extra magnification may not be useful in high glare conditions, such as when facing the afternoon sun and looking into shaded areas, or on overcast days in general. Also, I have a nit about some manufacturers who claim that their scopes have higher magnification ratio than they really have. Some of these wide ratio scopes don’t actually give you a wide ratio in the field of view. Instead, the field of view stops increasing at some point before the minimum zoom value is reached. As the zoom is decreased further, the entire sight picture starts to decrease. The magnification decreases, but the field of view stays constant. It appears as though the scope is being pulled away from your eye. For a hunting scope, the primary motivation for turning the zoom down is to see more of the target area. A wider field of view speeds up target acquisition and provides better situational awareness. If the scope doesn’t increase the field of view, then reducing the magnification isn’t very useful to me. As far as I’m concerned, the lower end of the range is that magnification at which the field of view stops increasing. Here are three examples: On the S&B 5-25x50, the field of view stops increasing below 7X. In my book that makes it really 3.6:1 zoom ratio, not 5:1. On the US Optics LR-17 3.5-17x50 it happens below 6X, making it really 2.8:1 zoom ratio, not 4.9:1, On the Bushnell HDMR 3.2-21x50 it happens below about 4.5X, making it really 4.7:1 zoom ratio, not 6.6:1. Still, there is one thing in their favor. Another reason to reduce the magnification is to increase brightness in low light conditions by increasing the exit pupil. Fortunately, on the all wide ratio scopes I’ve inspected, the exit pupil does increase all they way to lowest magnification. Not all wide ratio scopes have this problem. The Swarovski Z5 and Z6 scopes I’ve looked at increase the field of view all the way down to the lowest magnification. [/QUOTE]
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High magnification range - advantages/disadvantages?
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