I am about to buy some binoculars and am looking at the vortex diamondback 8x42. Low light is important to me and I have calculated exit pupil size etc (I'm 40) and I could probably use 8x50 but they are probably too big. So I probably should buy the 8x42 but want the 10x42. Even though the lower magnification will be brighter does that mean I am better off or could the 10x work as well. example at home lights on glasses off eyesight terrible. Lights off glasses on eyesight better.