I am looking at a Leupold VX3i 4.5-14 with 30mm main tube,and debating between the 40mm and 50mm objective lense, if I go with the 50mm I will need high rings if I go with the 40mm I can use regular height rings, will the 50mm make much of a difference in low light situations, this will be going on my deer rifle.
andy61
What is your deer rifle's caliber and from how far do you plan on shooting a deer?
If you are using a 336 in 30-30 or .35, you are honestly limited to 150-200 yards. A 40 or 50mm objective will give you more light intake, but within reason, it's more than you would ever need with one of these calibers.
I have a 32mm objective scope, that is not the quality of a Leupold, on my .35 and it provides plenty of light for shooting at dusk.
I also have a 20mm objective Leupold on a 30-30 and that also gives me good vision at dusk.
Lastly, my Remington 700 in 30-06 wears a 40mm Leupold. This rifle will shoot out well past 200 yards and I sometimes need more light gathering at those ranges.
Andrew
If you are using a 336 in 30-30 or .35, you are honestly limited to 150-200 yards. A 40 or 50mm objective will give you more light intake, but within reason, it's more than you would ever need with one of these calibers.
I have a 32mm objective scope, that is not the quality of a Leupold, on my .35 and it provides plenty of light for shooting at dusk.
I also have a 20mm objective Leupold on a 30-30 and that also gives me good vision at dusk.
Lastly, my Remington 700 in 30-06 wears a 40mm Leupold. This rifle will shoot out well past 200 yards and I sometimes need more light gathering at those ranges.
Andrew
I have to say that I am a huge proponent for the 50mm objective. I have 32's, 40's, 42's and 50's. In the woods before dark the 50mm out shines them all for me, and yes, they are all the same brand. I never realized just how much until a few years ago when I spent a lot of late PM time chasing a specific buck. The 50mm actually made the woods brighter than my naked eyes. I had never realized that before. For a late PM deer gun....I say 50mm!
DR
DR
Depends on what you use it for and what magnification. Your eye can only except so much light. Depends on the gun, cartridge, game, paper shooting, etc.
How old are you? The ability of the eye's pupil to dilate decreases with age. At age 20 most eyes can dilate to 8mm or 9mm. By age 60, your eyes (and mine) will only dilate to about 6mm.
Stay with me... This explanation assumes a poorly lit image, such as at sunset. We'll assume both scopes are identical except for the size of their objective lenses.
Scopes have a parameter known as "exit pupil". This number is calculated by dividing the diameter of the objective lens by the magnification.
Your eye dilated to 6mm (we'll assume you're 60) can use the full exit pupil of the scope (maximum brightness) at 6.66x with the 40mm objective lens. (40/6=6.66) With the 50mm objective, your eye can use the maximum brightness up to 8.33x. (50/6=8.33) Decreasing the magnification of the scope does not increase the apparent brightness, it only enlarges the exit pupil beyond 6mm, but your eye can only use 6mm of it. Even if the exit pupil is 8mm, your eye can only use 6mm of it, and the rest of the light is blocked out by your iris.
At magnifications higher than those above, the exit pupil of the scope is smaller than your eye's pupil, and the image seems less bright than images at lower magnifications, since it's smaller than your eye's pupil.
All this means that "light gathering" has a practical maximum. This maximum is the magnification of the scope at which the exit pupil matches the maximum dilation of your eye pupil. Let's stay with our 6mm eye pupil. Maximum brightness will be at 6.66x and below to 4.5x (it's a 4.5-14.5x40mm scope, remember?) and 8.33x and down to 4.5x for the 50mm scope.
So the question is, "How much magnification do you need at maximum light gathering capacity for your scope?" If you're ok with 6.66x you can save 200.00-400.00 from the price of the 50mm scope. If you think you need 8.33x at maximum brightness, you pay for the 50mm objective scope. Below 6.66x for the 40mm and 8.33x for the 50mm, both images will appear at the same brightness.
And with that larger objective, you also get several more ounces of weight and higher rings. You pays your money, (or saves your money) and you takes your choice.
I've always thought that 6x was plenty for my old eyes at maximum light gathering...
In brightly lit surroundings, (daylight) there is plenty of light for the eye to use even at 14.5x with an exit pupil of 2.75mm (40mm objective) or 3.45mm (50mm objective) and your eye pupil will constrict to limit light entry. Either scope will give an excellent image and you will not notice a difference in apparent brightness as your eye has more than enough light and it compensates the retina's sensitivity for optimum acuity.
Stay with me... This explanation assumes a poorly lit image, such as at sunset. We'll assume both scopes are identical except for the size of their objective lenses.
Scopes have a parameter known as "exit pupil". This number is calculated by dividing the diameter of the objective lens by the magnification.
Your eye dilated to 6mm (we'll assume you're 60) can use the full exit pupil of the scope (maximum brightness) at 6.66x with the 40mm objective lens. (40/6=6.66) With the 50mm objective, your eye can use the maximum brightness up to 8.33x. (50/6=8.33) Decreasing the magnification of the scope does not increase the apparent brightness, it only enlarges the exit pupil beyond 6mm, but your eye can only use 6mm of it. Even if the exit pupil is 8mm, your eye can only use 6mm of it, and the rest of the light is blocked out by your iris.
At magnifications higher than those above, the exit pupil of the scope is smaller than your eye's pupil, and the image seems less bright than images at lower magnifications, since it's smaller than your eye's pupil.
All this means that "light gathering" has a practical maximum. This maximum is the magnification of the scope at which the exit pupil matches the maximum dilation of your eye pupil. Let's stay with our 6mm eye pupil. Maximum brightness will be at 6.66x and below to 4.5x (it's a 4.5-14.5x40mm scope, remember?) and 8.33x and down to 4.5x for the 50mm scope.
So the question is, "How much magnification do you need at maximum light gathering capacity for your scope?" If you're ok with 6.66x you can save 200.00-400.00 from the price of the 50mm scope. If you think you need 8.33x at maximum brightness, you pay for the 50mm objective scope. Below 6.66x for the 40mm and 8.33x for the 50mm, both images will appear at the same brightness.
And with that larger objective, you also get several more ounces of weight and higher rings. You pays your money, (or saves your money) and you takes your choice.
I've always thought that 6x was plenty for my old eyes at maximum light gathering...
In brightly lit surroundings, (daylight) there is plenty of light for the eye to use even at 14.5x with an exit pupil of 2.75mm (40mm objective) or 3.45mm (50mm objective) and your eye pupil will constrict to limit light entry. Either scope will give an excellent image and you will not notice a difference in apparent brightness as your eye has more than enough light and it compensates the retina's sensitivity for optimum acuity.
I hunt in Ohio so I am limited to straight wall cartridge, it will be a marlin 375 so 200 yards is my maximum distance, with been almost 60 my eyes have been changing every year. I realize 14x is much more than needed for the range I will be shooting. I didn't realize with increased magnification light transmission was reduced,
For that gun this is what I would choose since big game is on the menu
https://www.leupold.com/scopes/rimfire-scopes/fx-ii-ultralight-2-5x20mm
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https://www.leupold.com/scopes/rimfire-scopes/fx-ii-ultralight-2-5x20mm
he would be very familiar with the Euro commonly encountered 6x42mm and 8x56mm scopes. Interestingly, both of those scopes have an optimum Exit Pupil -- 7mm. But take the 6x42mm scope and compare it to the 8x56mm scope and the difference in brightness is obvious, The 8x56mm scope, glass and coatings being equal, will win every time. This is true in spite of having greater magnification than the 6x42mm scope.The light "gathering" abilities of the larger, 56mm objective makes that big a difference.
What HIKayaker said about Exit Pupil is right on. The best (youngest) human pupils can only open to about 7mm. Some elderly pupils only open to 5mm or so. HIKayaker's 6mm example is a good one and probably applicable to most people on Marlin Owners.
However, there are other characteristics of optics to consider. One is Twilight Factor. The higher the Twilight Factor, the better the resolution of the scope when observing under dim light conditions. It is based on the notion that the larger the objective diameter the greater the amount of light it can "gather" for use by the optical system. The Twilight Factor is calculated by first multiplying the magnification by the objective lens diameter and then finding the square root of the result.. So, for example, at maximum magnification of 14x the 40mm scope would have a Twilight Factor equal to √ (14x40), or √560 = 23.7. At the same 14x the 50mm scope would have a Twilight Factor of √(14x50), or √700 = 26.5.
Another characteristic is Relative Brightness. Relative Brightness is calculated by squaring the diameter of the Exit Pupil. The higher the number, the better. This, too, can be calculated at any given magnification. For example, at 14X the 40mm scope has an Exit Pupil of 2.86mm, the 50mm scope an Exit Pupil of 3.57mm. Using those values results in a Relative Brightness at 14x of 8.16 for the 40mm scope and 12.75 for the 50mm scope.
Considering all three characteristics, Exit Pupil, Twilight Factor, Relative Brightness, between the two scopes suggests the 50mm scope would provide a clearer and brighter view in conditions like dusk and dawn or in places like the deep, dark woods.
However, the questions we must ask are, first, "Is that enough of a difference for the shooter to notice?, second, "If the shooter can see the difference, is it enough of a difference to matter or is the difference inconsequential?", and third, "Is the difference worth the extra cost, extra weight, and extra size?".
However, there are other characteristics of optics to consider. One is Twilight Factor. The higher the Twilight Factor, the better the resolution of the scope when observing under dim light conditions. It is based on the notion that the larger the objective diameter the greater the amount of light it can "gather" for use by the optical system. The Twilight Factor is calculated by first multiplying the magnification by the objective lens diameter and then finding the square root of the result.. So, for example, at maximum magnification of 14x the 40mm scope would have a Twilight Factor equal to √ (14x40), or √560 = 23.7. At the same 14x the 50mm scope would have a Twilight Factor of √(14x50), or √700 = 26.5.
Another characteristic is Relative Brightness. Relative Brightness is calculated by squaring the diameter of the Exit Pupil. The higher the number, the better. This, too, can be calculated at any given magnification. For example, at 14X the 40mm scope has an Exit Pupil of 2.86mm, the 50mm scope an Exit Pupil of 3.57mm. Using those values results in a Relative Brightness at 14x of 8.16 for the 40mm scope and 12.75 for the 50mm scope.
Considering all three characteristics, Exit Pupil, Twilight Factor, Relative Brightness, between the two scopes suggests the 50mm scope would provide a clearer and brighter view in conditions like dusk and dawn or in places like the deep, dark woods.
However, the questions we must ask are, first, "Is that enough of a difference for the shooter to notice?, second, "If the shooter can see the difference, is it enough of a difference to matter or is the difference inconsequential?", and third, "Is the difference worth the extra cost, extra weight, and extra size?".
Grenadier, the other thing that influences me is I have spent over half my life shooting foxes at first and last light and at night with a lamp (red filter and dimer switch). before we went to NV. I shoot many Deer is low light conditions where others would not (because I have cull figures to hit) and if needed my dogs are in the land rover. I use the best low light gathering scopes I can, My 30-30 has a 3-12x50 Leupold fire dot, that illuminated centre dot makes such shots possible. This works for me simple as that, in the conditions I shoot in, Gar.
I have the leupold 4.5-14x40 with 30mm tube great scope I've never been a fan of 50 mm . This particular scope isn't much bigger than a 3-9 x40 . My eyes don't see as good as they used to and generally shoot deer on about 6x to get a good look at the horns. They extra power is good for me when trying to find really small but legal horns .
The 50mm bell is all marketing, at least when it comes to Leupold. I was shooting late one night at the range to take advantage of no wind. The guy next to me said I was just wasting ammo shooting so late. I then asked him to walk down to my 100 yard target. There, we both seen several three shot groups under 3/4 of an inch. This was with an old Leupold Vari x3 3.5-10x with 40mm bell. This was at least a good 20 minutes past legal shooting time for hunting in our state. So, what would be the point to mount a scope higher than I would like that cannot be used during legal shooting hours? The newer Leupold VX5HD's that I own are basically night vision compared to the older Vari x3's, and they have 44mm bells. I understand night hunting for coyotes and such, but for legal big game hunting the Leupold's with smaller bells will more than suffice during legal hunting hours.
Some of the calculated values assumes 100% transmission of light coming from the object being viewed. No optical device, including the eye itself, is totally free of reflection. The coating on the objective lens of a scope (and on internal lenses) is to reduce the reflection of visible light and pass the maximum possible light, because any light reflected by any lens in the scope never reaches the shooter’s eye.
I had a friend tell me he had a 1x scope that made objects brighter when viewed through that scope than when viewed with the naked eye. I told him that had to perception, because light passing through any transparent object won’t be as bright on the other side no matter how clear the object. So a scope that magnifies is magnifying light, but some light is lost on the way through. The magnification overcomes the light lost from reflection, making the image appear brighter. My background; fiber optic cable splicing, testing, optical equipment (laser) power measurement, etc.
I had a friend tell me he had a 1x scope that made objects brighter when viewed through that scope than when viewed with the naked eye. I told him that had to perception, because light passing through any transparent object won’t be as bright on the other side no matter how clear the object. So a scope that magnifies is magnifying light, but some light is lost on the way through. The magnification overcomes the light lost from reflection, making the image appear brighter. My background; fiber optic cable splicing, testing, optical equipment (laser) power measurement, etc.
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