Awhile back, I talked with the Leupold sales rep at the Houston Safari Club show. He was telling me that when he did training for the dealers, he liked to ask what scope did they think was the brightest. Everyone would say a 50mm objective with a 30mm tube. the answer was the 2.5x8 VXIII.
It is the relationship to the lenses in the tube that transmit more light than size of the lenses. I have a few of those scopes now. For a long time, I had Swarovski a 7x50 binocular that had a 7.1 mm exit pupil. These were close to the best low light binocular available. When we would have parties I would bring non-hunters out on my front porch and have them look around at night and they would be amazed at what they could see in the dark.
I am telling you, I have had Leupold 2.5x8 VXIII scopes out with my Swarovski 7X50 binocular for ever to compare when the sun is going up or down and the difference is very minimal.
I do value great optics and use Swarovski, Zeiss, Bausch & Lomb Elite binoculars. The Leupold VXIII is a great riflescope.
As a footnote, I bought a Maven C2 7x28 binocular to keep in my vehicle always as something I wouldn't care if it got stolen. It was a $175.00 purchase and they have been fantastic. I imagine their B Series must be something else for the money.