Sorry to join a forum just to ask a question, but I hope you will believe that I did my best to research this subject before asking for your help. I have ground/polished working glass lenses before, and this time I want to make a perhaps stupidly large rifle scope that has acrylic lenses of THREE inch objective and a TWO inch eyepiece with 8X power (in case you wonder why so big, it's because i want to see whether large eyepieces really do help you sight your target better)
I know that magnification power is simply objective's focal length divided by eyepiece's focal length. But what if you have something like this?
I would need to "stretch" and/or "compress" the diverging/converging rays by adding additional lenses because, obviously, the 2:3 ratio of eyepiece:objective I want to (perhaps stupidly) design cannot produce an 8X magnification without it.
I apologize that, in some ways, I kind of know that maybe the answer might simply be to keep grinding and checking...by projecting an image into the objective and see if it comes out 8x smaller on the other end...until I get it right. But if anyone can give me any help, I would greatly, gratefully appreciate it.