scope, optics, objectiveI’ve recently purchased a Vortex Viper 6.5-20x44 scope. The objective lens, being 44mm, is one of the larger ones out there. What’s the exact purpose of a larger objective? I was told it allows more light to enter, providing a brighter image. Is there another purpose in addition to that?
In addition, what purpose does the larger tube serve? Mine has a 30mm tube vs. the other popular 25.4mm tubes. Do I gain any advantage with the larger tube?
I’ve seen many conflicting descriptions on both of these parts of the scope, yet never seen any kind of answer that was definitive.
The larger the objective lens, the more light the scope is allowed to gather. This allows the image to be clearer in lower overall light, such as during sunset or in the early morning. The larger the objective lens, the higher your scope rings will need to hold it above the base. Larger objective lenses also weigh more and increase the overall weight of the scope and rifle.
The diameter of a scope’s center tube affects the overall strength and durability of the scope, and determines the size of bases and rings required for mounting. But primarily, the center tube diameter affects the range of windage and elevation adjustment a scope is capable of having. A larger center tube will allow for a greater amount of adjustment. Less important for windage, but more important for elevation if you are shooting at very long ranges (adjusting up), or if you have a base with elevation adjustment built into it (like a 20 MOA base) and need to shoot at a close target (adjusting down).
There are scopes by Leupold in the VX-3L line that have a cutout of the bottom of the objective lens. From their site:
VX-3L® riflescopes combine the low-light performance of a larger objective VX-3 with a revolutionary design that hugs the barrel of your rifle. You’ll be amazed at the exceptional low-light performance and more natural cheek weld in your VX-3L, the ultimate low-light riflescope.
These allow up to 56mm objective lenses to be mounted in low height rings.
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