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Thread: Scopes and large objective lenses

  1. #1
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    Default Scopes and large objective lenses

    Well so now as most of you know Leupold has the VX-L scope with the 50mm objective lense. http://www.leupold.com/products/vx-l.htm This thing is HUGE! There are 44's and 40's, 36's, 32's, etc. on the market also. What do you all think about the larger objectives? The human eye can only let in a certain amount of light no matter how large the obj. lense on the scope. At some point a larger obj. is just a waste of metal and glass. I guess they sell though. I have studied this and just came across a very simple statement a guy made that sums it up:

    Depending on the power of magnification you intend to hunt with you may not need any more than 32mm. You see the human eye can only absorb so much light through the pupil. A young eye can go to 5mm, maximum. As you get older that reduces with time, 4mm and even less. The formula is simple, the capability of the eye X magnification = needed objective size. An older eye with a 8X scope can only utilize 32mm of objective (4x8=32), any larger is useless. A younger eye could take advantage of a 40mm bell at 8X, but how often does one hunt at max power. My biggest scope is a 2.5x8 Weaver and it doesn't spend a whole lot of time at 8x.
    -OR-
    obj. lens divided by power = exit pupil. My leupy 2.5-8x36... 36/2.5=14.4 exit pupil.

    How much larger than 40 does a guy really need? When the 40's came out they were considered huge. My postition is that bigger is not necessarily better when it comes to scopes.

  2. #2
    Member svehunter's Avatar
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    Default

    Maybe a sheep hunter needs 50 mm or more

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    On a rifle scope? I shot mine at 400yds with my 36mm at 8x. I have a friend who has an old 4x weaver that can't be much larger than 36 or 40.

    Maybe with a 50mm you could use a little higher power in low light. But the higher power you go the dimmer it gets.

    Anybody using one of these big scopes that can give us the scoop?

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    Well, I've used one but it was a Zeiss 2.5 x 10 x 56. I used to hunt in Germany. It also had a German number 4 crosshair. There you hunt wild boar off a stand at night. I shot three right around midnight (different nights). The large objective allowed me to see their silhouette with just a little moon light. I took it off the rifle since, after four years back in the states, I didn't have a need for the large objective.

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    56mm, wow, that's huge. Never knew they even made them that big.

  6. #6

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    I have a 4-12x50 swaro av w/ tds on a 300rum......it is lighter then the compitition and view/eye relief are awesome.

    I have a second 300rum that just got a 2.5-10x50 illuminated 4200 pulled off cause it is way to big and heavy......it now wears a 3-9x 40 burris

  7. #7
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    Default Objective size

    On a recent hunt (Texas Deer) my 10x25 pocket binos were virtually worthless at twilight; however I could see thru my scope with a 40mm objective. It gave me about 10 minutes of extra primetime hunting. I do believe the larger objective is better in this particular situation.
    An unarmed person is a victim waiting to happen.

  8. #8
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    ya, 10x25's in low light are'nt to good. only a 2.5mm exit pupil. Your 40mm scope on 3x is a 13.3mm exit pupil. Even on 9x it is 4.4 mm. Usuly the lower power is what makes the big difference.

    It would be interesting to see some direct comparisons between say a 36mm scope at 3x and a 50mm scope at 3x side by side in the same low light to see if there is any noticable difference. According to what they say, anything above 5mm exit pupil won't matter because that's all the bigger the human pupil is. Anyone done anything like this?

  9. #9
    New member AkBubba's Avatar
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    Default Yes they do

    Quote Originally Posted by Snyd View Post
    56mm, wow, that's huge. Never knew they even made them that big.
    My NXS has a 56mm

    Amazing clarity in low light.

  10. #10

    Default Large objectives

    While large objectives will add to the total light allowed in (to a degree); what it will do is increase the size and weight of the scope; thus increasing the overall weight of the shooters rifle. Something for mountaineers to consider.

  11. #11
    Member Roger's Avatar
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    Quote Originally Posted by Snyd View Post
    56mm, wow, that's huge. Never knew they even made them that big.
    They make a 80 mm scope ,I use an ATN 4-12 x 60 on my moose rifle , I love it at dusk gathers alot of light.

    Heres a link if you want to check one out

    http://www.securityandsafetysupply.c...flescope-5.htm

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