The Leopold VX-II 2-7x33mm scope was designed to be a mid-range scope, ie "thick woods", and with the Multicoat 4 lens, as stated by Leopold, "Unparalleled light transmission in all light conditions.."
Basically, enhanced image clarity in all light levels, "Dusk or Dawn"....
Quick, the VX-II 3-9X40 also has multicoat 4 lens.
My point being the objective dia.. Personally,I would rather have a larger objective dia. in low light condition's (such as in thick wood's) for better light gathering capabilities than a small objective.
Personal opinion only, to each there own, thank's for your input.
I guess it's safe to say, "It's all in preference..."
VX-II 3-9x40mm compared to the VX-II 2-7x33mm is a 1.4 inch longer than the VX-II 2-7x33mm, weighs about 2 oz. more, and comes with a little heavier price tag....
The actual Objective Diameter of the VX-II 3-9x40mm, is only, .2 inches or basically 1/5 of an inch larger than it's less expensive predecessor.
In General the VX-II 3-9x40mm is just a bulkier and longer scope than the slimmed down VX-II 2-7x33mm. If an individual was seeking a little extra light and that would justify the higher price, length and weight, I guess the VX-II 3-9x40mm might be a better choice. But, once again, "It's all in preference...."
Well, if you do the math you find that at maximum magnification the 2-7x33 has a larger exit pupil than the 3-9x40, meaning that it should pass more light. Of course, if you turn the 3-9x40 down to 7 power--which is more of an apples to apples comparison--then it has a larger exit pupil and should pass more light. So, the question is, are you comparing them at equal magnifications or at each one's maximum magnification?
Personally, I would just get a fixed 4x scope since I've never found greater magnification than that to be very useful.
The VX-II 3-9x40mm passes a larger beam of light, as expected.
So, basically, a 7mm increase in diameter of an objective lens from 33mm to 40mm, increases the exit pupil size, along with the size of the light beam, by 1mm. So, the size of the objective lens is directly related to exit pupil size but the exit pupil size is not directly related to the light itself.
A better approach to analyzing the "light gathering ability" is to look at brightness which is determined by the quality of the lens, objective diameter, lens coating, and the overall scope resolution....
Ideally, the exit pupil is nothing more than a variable which dictates the size of the light beam that reaches the eye and has nothing to do with brightness or resolution which are the key factors during dawn & dusk light conditions.
I don't know where everyone hunts, but where I do, there isn't a scope made that extends legal shooting hours. I can see perfectly well through any of my scopes when legal shooting begins and ends, although some are brighter than others. So for me, weight, size, and how it affects the balance of the rifle are all far more important.
I agree mister venison. I purchase a scope for its reliability, weight, and eye relief and after hours brightness has never been a deciding factor. I have always used Leupold scopes on my rifles and have never been disappointed or let down. I want to try the Bushnell elite series but am too chicken to switch something that has performed flawlessly.
How useful is a scope, which may be perfectly balanced, light as a feather, and can be held at a comfortable distance from the eye, if, the image isn't bright, clear, and crisp?
But then again, what good is it to have the "Hubble Telescope" mounted to your 30.06, if it's to heavy to carry, and not well balanced?
As far as the dawn & dusk scenario goes, when used in the context of scopes, it is merely a test which is used to scale the quality of the objective lens glass, lens coating, prisim, and overall resolution by determining if the image has bright colors opposite to being washed out, clear as opposed to being dark, and crisp verse being blurry.
Not to be confused with testing a scope for "Poaching Ability"....
As a Taxidermist I look at hundreds of Whitetail Bucks every year. I know that I have seen many different ways people judge the size of racks on live deer. I think for the most part they all are pretty close. I'm going to give you some measurements that I have noticed being right on in just about every deer. We have used it in the last couple years and have only been off by about 5-6 inches. We do study the deer while bowhunting so we get a little more time to look at them....