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Old August 7, 2012, 06:10 PM   #1
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What is the difference in scopes magnification?

Can someone tell me in plain words what the difference in scope magnification really means. Am set on a leupold now but will like to know what the difference is from vx1 and vx2. Also the difference in 3-9x40 and 3-9x50. Excuse my ignorance but the guy at pro bass left more ? Than answers. Thanks alot.
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Old August 7, 2012, 06:15 PM   #2
Brian Pfleuger
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The 40 and 50 is the size of the front lens in millimeters, not magnification.

They both magnify from 3x to 9x, one has a 40mm front lens, the other a 50. In theory, all else being equal, the 50 let's in more light, will be better in low light.
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Old August 7, 2012, 06:29 PM   #3
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Thanks got one out of the way.
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Old August 7, 2012, 06:31 PM   #4
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what the difference is from vx1 and vx2.
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Old August 7, 2012, 06:33 PM   #5
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the guy at pro bass left more ? Than answers.
What a shocker there.

And... I blew my 1000th post being a smarta$$.

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Old August 7, 2012, 09:47 PM   #6
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Make sure the scope fits your rifle and you well. If it does not, your accuracy will suffer.

I would rather have a clear and sharp 2x or 3x than a 9x that is not all that clear and sharp. IMO, image clarity, low light ability and ability in bright sunlight (I hunt) is much more important than the power of the optics. I also prefer a wide field of view for quick target acquisition. Under what conditions will the rifle and scope be used?
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Old August 7, 2012, 10:22 PM   #7
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The difference...

between VX-1 and VX-2 is that the "2" has more/better lens coatings, resulting in better light transmission. Something on the order of 90% for "1", vs. 94% for "2".

The 50mm objective lens collects more light than the 40mm, resulting in a bigger "exit pupil" diameter. The bigger the scope exit pupil diameter, the more light goes into the pupil of your eye. In the early morning, when first light dawns, the pupil of your eye is wide open - about 7mm in diameter for young eyes, but us old farts pupils are limited to a maximum of about 4.5mm diameter. Therefore, any scope with an exit pupil diameter less than our wide open pupil will cause us to see a dim image in our scope.

To calculate the size of your scope exit pupil, divide the objective lens diameter by the magnification. Example: 50mm objective set on 5X magnification results in a 10mm scope exit pupil - 3mm bigger than the youngest eyes can use. 40mm scope objective lens set on 5x equals 8mm scope exit pupil. Again too much to be used, but not by much. So, at 5X magnification, both the 50mm and the 40mm objective lens will give a bright picture.

But, if you want to use maximum magnification in first light, the 50mm lets you do that. Example:50mm objective, 7X magnification, equals an exit pupil of 7+ mm. 40mm objective, 7X magnification equals less than 6mm exit pupil.

Once the sun comes up, you will still have some dimly lit shady spots where good light gathering optics are needed.
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Old August 8, 2012, 12:37 AM   #8
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The larger objective lens (50mm) will need taller scope mounts. That will raise the line of site higher in relation to the barrel and the stock. This increase in hight can cause less accurate shooting because it reduces cheek weld (holding the stock tightly to your face helps steady the rifle). The increase in hight also changes the trajectory of the cartridge slightly. Most hunters probably won't notice the difference but it is more apparent at longer ranges.
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Old August 8, 2012, 07:49 AM   #9
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Don't waste money on a 50mm front objective. The amount of light that gets through to your eye is a factor of several things. The front objective is only one of them. You also have to consider the scopes magnification, and light transmission rating.

Assuming equal quality glass a 50mm scope set on 10X lets in exactly the same amount of light as a 40mm scope set on 8X or a 20mm scope set on 4X. These 2 factors (front objective diameter divided by the scopes magnification) determine the diameter of a ray of light coming through the scope. Imagine a beam of light from a flashlight. You can adjust the beam from a large circle or a narrow circle. All of the above examples will let in a beam of light to your eye 5mm in diameter. That is about as large as the average human eye can dialate. Any more light is wasted. If you are still in your 20's with exceptional vision you might dialate to as much as 7mm.

But even this does not tell you how much light is getting through, only the diameter of the beam of light. The scopes light transmission rating tells you how much light gets through. Many scopes in the $200 and under range only let around 80-85% of the light that enters the front objective through to your eye regardless of how large the beam of light is. The better mid-range scopes are in the 90-95% range. Your really high end scopes are in the 95-98% range.

A decent $200-$300 mid range scope with a light transmission rating of around 90-95% with a 40mm objective will be far better in low light than a 50mm scope with a light transmission rating of only 80-85%. A scope with a 50mm lense, and 90% or greater light transmission is far more expensive than a 40mm scope with the same rating.

A 50mm scope is only an advanage at 10X. At any other power setting it lets in no more useable light than a 40mm scope. It is only an advantage for 2-3 minutes in the morning, and another 2-3 minutes in the evening, and only if you spend big money to get a high end scope with at least a 95% light transmission rating. Otherwise you are wasting money.
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Old August 8, 2012, 08:47 AM   #10
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Don't waste money on a 50mm front objective.
BIG PLUS ONE!!! Personally I don't even like the 40mm objectives (too big) and think they are unnecessary. Also, on a hunting gun don't let ANYONE talk you into anything with more magnification than the 3-9x's you're looking at and don't count out the great 2-7x scopes on the market.
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Old August 8, 2012, 12:34 PM   #11
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I think JMR40 nailed it. Most people beyound 40 can't use the extra light a 50mm lens provides. Quality glass on the other hand is important. You get what you pay for, though the cost goes up a lot faster than the difference in quality. 9 power is plenty for anyone except the few highly skilled individuals who have practiced a great deal at distances over 300 yards. 99% of all hunters including myself have no business shooting over 300. What ever happened to the skill of stalking close to your game? Perhaps this is why bowhunting is growing so much in popularity.
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Old August 9, 2012, 09:10 AM   #12
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One advantage of a 50 over the 40 is the field of view (area surrounding the target). A lot of difference if you compare a 4x15 (22 scope) or your 3-9x50 set on 4x. Besides the light gathering qualities, that is one of the main reasons that the scope manufactures upped the front lens sizes. A lot of the old scopes had a 32 or 35 lens. Then they went to 40, and then the 44 and now they even go up to 56.
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Old August 9, 2012, 10:47 PM   #13
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Thanks alot guys. All of you have been really helpfull thanks for taking the time to pass on what you have learn over the years. Am 30 years old and started hunting deer 3 years ago got my first 4 poiter last year with a mini 30 and realy wanted a hunting rifle. I think am ready for this year and years to come got my self a tikka t3 lite ss in 270 with a leupold vx-2 3-9x40 in silver to match the berrel. Everyone's advise was consider in making my decision. Will let you guys know how it does onece i take it to the range. Thanks again.
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Old August 9, 2012, 11:05 PM   #14
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I use 3x9x40mm scopes on everything from a 22 to a mini-30 to my 308's. I seldom have to magnify any higher than 5 or 6 power, but sometimes when target shooting I will go to the 9x now and then.

On my Saiga 12 gauge (slug-shooter) I have a 1.5 x 6 x 32mm. A heavy duty mount to help with the stronger recoil of the shotgun. I took a couple of large Hogs last year with it.
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Old August 15, 2012, 11:07 PM   #15
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sc928porsche, The objective size has nothing to do with FOV that is determined by magification.

FOV @ 100yds. Low mag. High mag.
VX3 4.5-14x40 19.9' - 7.4'
VX3 4.5-14x50 19.1' - 7.4'
VX3 1.5-5x20 68.0' - 23.8'
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Old August 15, 2012, 11:30 PM   #16
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Thank you mike7.62 for setting the record straight. Besides that, the objective lens size only needs to be large if you use very high power. For very low light conditions, you want the objective to be 5 times the power, so 45 (or 44) for a 3-9x variable. But if you have a 3-9x by 36 mm, then just dial down to 7x to get the most light gathering your eye can use.

And of course, the quality of the glass and it's coatings make more of a difference than the objective lens size, so choose wisely.
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Old August 15, 2012, 11:44 PM   #17
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Les, that stainless Tikka in .270 Win with a silver VX-2 3-9x40 will be a great combination that will last you a lifetime! You will love it! Great choice!

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