This may be a stupid question, but I will go for it anyway because a local camera/telescope store had answered this question I believe in error. Example in one scope one uses a 1.25” diagonal and a 1.25” eyepiece with lets say 82 degree AFOV, and another scope {identical scopes} with 2” diagonal and 2” eyepiece with 82 degree AFOV, {both eyepieces with same FL} I say the true field of view is the same. The dealer says the port hole effect will be greater with the 2” diag combo. If true field is true field then it should not make a difference. If I am right then why use 2” eyepieces in certain focal lengths that are available in 1.25”?
Paul