BIGGER APERTURE = more brightness in screen?

Hi guys,

Newbie here and perhaps stupid question i am throwing here but i am so curious.

I noticed that when I used 85 3.5 micro and used it at 3.5 aperture, my camera screen was not bright. But when i switched to my 17-50 2.8 tamron, and used it at 3.5, the screen is actually brighter.

my question is:

1) is it true that bigger aperture actually yields to brighter screen on camera?

2) can anyone explain to me if this is the case, why is that?? i mean, i used both at 3.5 but why the one with BIGGER maximum aperture results in brighter screen?

Thank you.