nikon, leupold, or redfield

Why dead set on 50mm glass? I would get a VX-II in 3-9x40mm

How much is the VXII?

Leupold

Nikon

quote:

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I would get a VX-II in 3-9x40mm

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Plus 1.

Anyway, many, many people believe that the larger the objective lens size the more light you will see in dim conditions (or light gathering as so many like to say). It seems logical to the mind, a bigger lens grabs more light. But is this true? Does a 50mm objective actually give a brighter image than a 28mm objective? The answer is, yes and no. The larger objective only shows benefits as you increase the magnification of the scope.

Here's how it works...

First, on the average a human eye's pupil is around 5-7mm in diameter. Any number larger than the actual size of your pupil does not matter because the eye cannot make use of it. This will make more sense in a bit.

A scope's objective lens determines its exit pupil. Ya know how when you're head is too far back and you start getting that black ring around the view? That is the exit pupil beginning to show itself. Your eye doesn't see it when everything is properly aligned, but it is there and the size of the exit pupil gets smaller as the magnification increases. And the smaller the objective lens, the smaller the exit pupil. So magnification and the size of the objective lens are correlated and it does make a difference. But then...

There is a pretty simple formula for figuring this stuff out: Divide the objective lens size by the magnification setting to get the exit pupil. Now remember, an exit pupil any larger than the actual size of your eye's pupil (5-7mm) is just wasted.

Let's look at a few examples:

1. A 3-9x36mm scope. To find the exit pupil size on a setting of 3x you divide it into the objective lens size of 36mm. So, 36/3=12mm. On a setting of 6x it is going to be 6mm (36/6) and on a setting of 9x it is going to be 4mm (36/9).

2. A 3-9x40mm scope. 40/3=13.3mm and 40/9=4.4mm.

3. A 4-12X50mm scope. 50/4=12.5mm and 50/12=4.2mm and when set on 9x it equals 5.5mm (50/9).

4. A 2-7x32mm scope. 32/2=16mm and 32/7=4.8mm and when on 6x it equals 5.3mm (32/6).

5. A 2.5x28mm scope. 28/2.5 equals 11.2mm (28/2.5 ).

So what does all that mean? Note that in all of the above examples, when on the lowest setting the number is greater than the size of the human pupil. As we increase the magnification that number begins to drop but the larger objectives gives a higher number than the smaller ones. Any time that number drops below the actual size of your eye's pupil, then you're losing light transmission. Ideally, the actual size of your eye is never more than the number the formula spits out.

Basically, if you're going to spend the majority of your time on low magnification settings, the size of the objective just doesn't really play a role as even the small objectives will theoretically transmit more than enough light for the human eye. However, if you're going to start cranking that magnification up in low light conditions, then the size of the objective becomes increasingly important as the magnification goes up. Note the differences in the 9x settings in the first three examples.

Now, I say a larger objective at higher magnifications should theoretically transmit more light because it isn't necessarily so. Yes, the formula is sound but what it does not take into consideration is the actual glass itself and the overall construction of the scope.

A substantial portion of a scope's ability to transfer light to the eye is dependent on the glass; how it is ground, how it is installed/aligned, the coatings, the quality of the glass itself, etc. this is where a lot of your money goes when buying scopes. A 50mm scope with really poor glass coatings and such is probably going to be worse at high magnification than say a 30mm scope with really good coatings and such at the same settings . A scope can have the physical dimensions to transfer that light but if it lacks the other necessary components to let the eye see it clearly then it really doesn't matter.

Rize knows how to copy and paste

Trying to get my $160 Mueller out to the range soon. It is much nicer than other scopes in that range

just got back to my post.. watching movie with the wife but going to read that long arse post later! thanks guys

I got the Nikon Buckmaster 3-9 X 40 around Christmas for $182. It has the BDC (bullet drop compensator), and supposedly has a better glass than the Prostaff. Look around if thinking about Prostaff and see if you can find comparable prices in the Buckmaster