1.25" vs. 2" eyepieces

This probably reveals my newbie status, but it seems to me that a 2" eyepiece would have more light flowing through it than a 1.25" eyepiece, but thought I read in a post recently that it doesn't really matter. Is aperture only important on the front-end of the scope? Wouldn't that also mean that a 1.25" diagonal should perform just as well as a 2"? I also have seen a number of high end eyepieces that have both 1.25" and 2" skirts, and if it did make a difference in performance you'd think companies would make both models instead of just making a 1.25" diameter EP fit into a 2" hole. Is this just personal preference?

Enlightenment desired (no pun intended, really).

Paul

The advantage of a 2" eyepiece has nothing to do with how much light it passes. The telescope produces an image at prime focus. Ignoring possible vignetting, each part of the image uses the entire aperture, which is what determines how much light is collected.

Inside the eyepiece is a field stop - a ring that defines the outer edge of the eyepiece's field of view. The diameter of this ring and the focal length of the telescope define the telescope's true field of view. Because a 2" eyepiece is larger than a 1.25" eyepiece, it can have a larger field stop, and provide a larger true field than a 1.25" eyepiece.