ORIGINAL: Alsatian
There is a relationship between objective lens size and magnification. Thus, if your scope magnification is lower, you don't need as large an objective lens.
Not true...You can have just as much magnification with a small lense as with a larger lense...however the light gathering ability is less. Magnification is more related to the curvature of the lense rather than the diameter of the lense. A lower power lense will have a greater brightness than a higher power lense if the diameter is the same.