Contrast vs. Brightness

A scenario that is not just theoretical . . .

I'm comparing several types of identical focal length eyepieces for higher power viewing of both planetary and brighter compact deep sky objects (globulars, planetaries, etc). While the views are sharp in all three, light throughput and contrast vary significantly. Some have brighter images with less contrast (Orion's Expanses), and the others slightly dimmer images but a perfect black background (Vixen LV's).

Unfortunately, without Jupiter and Saturn to compare them on right now, its difficult to determine which will offer better views in the long run. So, from all you observing experts out there, which in your opinion is more important in an eyepiece - BRIGHTNESS (light throughput) or CONTRAST?

Thanks for your always enlightening opinions.

For planets, I'd take the vixen over the expanse. I've used both a 6mm vixen lv and a borrowed 6mm expanse. The expanse gave nice deep sky views (especially for the $ - holy cow!), but on bright objects was plagued by internal reflections and scattered light. Jupiter, when off-center, produced a terrifyingly bright reflection.

If your question is choosing between these 2 eps for planetary viewing, then I strongly recommend the vixen. For your more general question of brightness vs. contrast...I don't consider myself an expert observer, but I suspect the experts will chime in on the side of contrast (again, if your main concern is planetary viewing).

Just to complicate the matter, our visual system's sensitivity to contrast varies with the overall brightness of the image.