So I have a maple stocked, octagon barrel bolt rifle showing up inn under two weeks. I do like the lines on it for some odd reason, so vodka and impulse win again.
So that comes to the optics end, i want to purchase my rings at the same time and although it is a 7mm RM - I don't know if I can fathom the look of high rings and a 50mm objective lens sitting on a rifle that looks like that. What do you all think that a 50mm buys you for time at dusk or dawn over a 40mm scope?
I have a VXL sitting on my synthetic stock ugly knockabout rifle but never thought it truly made that much more of a difference at twilight..... Will more than likely stay within the 3i series and would still like to take full advantage of the 7's reach out and touch them trajectory.
Yes, I know it is a very odd rig but
Dirk
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This is an interesting read,... not too many people know this....
SHORT ANSWER:
In practical terms, the 50mm scope will be brighter than a 40mm scope only under a combination of the highest magnifications and the very darkest conditions. Otherwise, a 50mm scope is delivering more light than your eye can use. In addition, a 50mm scope will pull your head up off the stock and also be heavier as well as more expensive than a similar model in 40mm.
The big objective is a hard myth to bust because we have become so conditioned to bigger is better. On a riflescope a bigger objective does not always guarantee a brighter image. Here's why...
LONG ANSWER:
The scope:
The exit pupil on a riflescope is the actual width of the beam of light that leaves the eyepiece. If the beam of light that leaves the eyepiece is larger than the opening in your eye, the riflescope is delivering more light than your eye can use. You can calculate the width of this beam of light (exit pupil) in millimeters on your riflescope by dividing objective size by the magnification setting. A 3-9x50 set at 5x produces a 10mm exit pupil (50 divided by 5). A 3-9x50 set at 8x produces a 6.25mm exit pupil (50 divided by eight) . The higher the magnification setting, the smaller the exit pupil (beam of light) your scope produces.
YOUR EYE:
In order for your eye to open to its maximum, you must be exposed to conditions of total darkenss for at least thirty minutes. Most people do not hunt under these situations, but for the sake of argument, let's say that they do. Under these conditions, the average widest a young persons eye can open is about 7mm (some individuals 8mm), but most folks who hit their forties will find their eyes can open no more than 5 or 6mm. By age 50, you're doing good at 5mm. It's part of the aging process.
According to the math, if your eyes can, and are, open to 7mm, a 3-9x50 delivers more light than your eye can use at magnifications below 7x. For eyes that are open to 6mm, magnifications below 8x waste light. For eyes that can only open to 5mm, magnifications below 10x waste light - in other words, all magnifications on a 3-9x50 when your eyes are only open to 5mm, deliver more light than your eye can use.
Since very few people hunt under total darkness, they will not be shooting with eyes that have opened to 7mm. Under typical low light situations, your eyes will be open to 4 - 6mm at best.
Once again, do the math. For eyes that are open to 5mm - typical for low light adapted eyes - a 40mm riflescope is still delivering more light than your eye can use at magnifications below 8x. Since most deer are shot at much lower magnifications than 8x, a 3-9x40 will do anything you need to do in terms of low light shooting. If you want to spend more money, you are dollars and performance ahead to invest in a better quality 3-9x40, rather than jump to a 3-9x50. Quality will have a greater impact on performance.
