Does anybody have experience using a binoviewer using the Nagler 13T6 and 9T6 eyepieces? I was wondering if the maintain there edge performance in a binoviewer? I am currently trying out a DeepSky Bino. I don't have the 1.2x corrector yet so I am using a Powermate 2.5x to get to focus. I am experiencing some loss in edge performance with this setup. Is this normal in a Bino?

Thanks,

David