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1-4x, 1-6x, 1-8x exit pupil on 1x

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Chrome223 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Chrome223 Quote  Post ReplyReply Direct Link To This Post Topic: 1-4x, 1-6x, 1-8x exit pupil on 1x
    Posted: January/06/2020 at 20:13
Somebody remind me why the higher magnification range LPVOs generally have a worse eyebox on 1x.  

On paper, exit pupil is just the objective lens divided by the magnification, so on 1x two different optics with different maximum magnifications but the same size objective lenses would have the same exit pupil. 

So why do 1-4x optics generally have more forgiving eyebox than a 1-6x.  Is the effective exit pupil somehow smaller on the 1-6 or is something else going on making it harder to get the most out of the objective lens size?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rancid Coolaid Quote  Post ReplyReply Direct Link To This Post Posted: January/06/2020 at 21:31
Someone else will have to get technical, but I can agree 100% that all 1-4X eye boxes are not created equal - regardless of where you sit in the mag range.

So there is more to it than just objective diameter, probably some witchcraft and a bit of voodoo, maybe some narwhal tusk too.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote koshkin Quote  Post ReplyReply Direct Link To This Post Posted: January/06/2020 at 23:02
The formula for calculating exit pupil does not work for the entire magnification range.  Virtually all riflescopes have a smaller exit pupil on low power than the ratio between objective and magnification.

The larger the erector ration, the harder it is to keep a large exit pupil on low power, so if all else is equal a 1-4x will have a larger exit pupil on low power than 1-8x.

For example, March generally focuses on high erector ration riflescopes, but for driven game and other applications where you need speed on 1x, they make a 1-4x24 riflescope with a bright FlashDot reticle and 18mm exit pupil on 1x.

Their 1-8x24 Shorty riflescope has a 7mm or thereabouts exit pupil on 1x.

ILya
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