Roof bins: is it normal this when closing?

[Glimmer]

I tried a pair of new Minox HG 10x42 and other roof models. When I close them to adjust them to my eyes distance (width) the brightness increase. Moreover, if I close them totally the brightness is higher that the bins in the position fo completely wide.

Is it normal for roof bins? With my porro bins this does not happen...

[Tero]

This would be normal for most binoculars that when the dihedral angle is adjusted for your eyes you get the best, brightest view. But it has to do with eye relief and how carefully you need to place your eyes, not porro or roof.

[ceasar]

Your binoculars will always be brightest when you have the exit pupil (That is the bright dot you see in the center of your ocular lenses when look at them while holding them away from your eyes) exactly centered over your pupils. You will have the same IPD in Roof Prism binoculars as you do in your Porro Prism binoculars.
Cordially,
Bob

[Glimmer]

Thank guys. But it's curious that the most brightest position of Minox HG is totally closed (and I don't have the eyes so near, be sure!) With Olympus DPS R I get it in a mid position...