3x9 vs 4x

[ChattanoogaPhil]

I did quite a lot of reading about scopes before my last purchase (probably just enough to make me dangerous) but I find myself disagreeing with a lot of what I read here, especially about needing a large 50mm objective on a 3-9x scope to get more light...

The exit pupil on a 3-9x 50mm will range from about 16mm at 3X to about 5.5mm at 9x. Varying with age and the individual... on a bright day the pupil of your eye is only about 2mm, 4mm around dusk, and a fully dilated pupil in total darkness is about 7+mm.. and if you are an old fart your pupils may not dilate much over 4mm. Midnight shooting?

All things being equal (especially when you are looking at dime store optics), the downside of a 50mm objective include a heavier scope, using tall rings and risers, further away from the bore, cheek weld complications, more parallax and not as good depth of view as a comparable 40mm.

 

[tacticool22]

A larger objective just gathers more information and has a larger field of view. The weight can be negligible to equal from a 50 to a 40. I know on long outings (Oregon Elk) ounces = pounds and pounds = pain.
My 50mm's co witniss with my iron sights. I made sure of this so I didn't have the different cheek weld, tall wobbly rings, no different parallax than any other scope and superior field of view. More information into the objective lens, more out to your eye.
My binocs are 12x50. The difference betweenthose and 10x50 is amazing. I tried a 12x30 and will never carry those again.
But this is all opinion of course.

 

[ChattanoogaPhil]

A larger objective just gathers more information and has a larger field of view.

From what I am reading... Simply buying a scope with a larger objective lens does not necessarily mean that you are getting a larger field of view.

For example: Bushnell 4200 scopes-- 2.5-10x 40mm and 50MM shows to have the same field of view (actually, the 40mm shows to have a slightly larger field of view at 2.5x.). // Someone mentioned Vortex. The Viper HS 44mm and 50mm show to have identical field of view.

It appears to me that the design of the scope (within the magnification range) has as much or more to do with the field of view than just grabbing the big one on the shelf.

Bushnell - Elite 4200 2.5-10 x 40mm, Matte [422104M]

 

[tacticool22]

Yes, there is a lot more to scopes than just the numbers on the outside of the box. Everything adds up to be a superior, marginal or inferior product. Nothing beats a side by side comparrison. Let your eyes decide before you break out your wallet. What is the greatest thing for one person can be nothing more than a paperweight and expensive lesson for another.

 

[ChattanoogaPhil]

Yes, there is a lot more to scopes than just the numbers on the outside of the box. Everything adds up to be a superior, marginal or inferior product. Nothing beats a side by side comparrison. Let your eyes decide before you break out your wallet. What is the greatest thing for one person can be nothing more than a paperweight and expensive lesson for another.

Field of view is a specific measure, not dependant on the user (absent glaucoma). But I do agree that there is a lot of myth and hype about optics that a side by side comparison can sometimes resolve as to the usefulness for the user.