brocknroller
porromaniac
I also notice the better light transmission in porros compared to roofs. If comparing "apples to apples", i.e. same magnification, objective size, and build quality I've always found the porros to be brighter. I don't think it's just more light being transmitted but how it's transmitted.
Several months ago over on the Cloudy Nights Binocular Forum there was a discussion about light transmission in porros and roofs where Edz pointed out that "roofs lose full illumination once you move away from dead center". I know on the night sky you can discern very faint objects better with averted vision because of the higher bias of rods vrs cones in the outer part of the pupil.
It makes sense to me that if porros spread the light out over a larger area of the pupil which is more efficient in gathering light a porro should have an inherent advantage in light transmission over a roof. In other words not just the total amount of light transmitted but how much of the percentage of light transmitted through the optical train can be utilized by the human eye.
Anyway I do a lot of terrestrial viewing in low light and I find porros better than roofs....more so than can be explained just by a porro transmitting more light.
Steve
P.S. Welcome to the forum
Are you talking about "full illumination of the exit pupil"? I brought this up a while ago, and Henry said that Edz had recanted on that theory. Has it been revived????
Brock