I don't have enough fingers to type up the last 4 years of this quest of mine to find the absolute best low light scope. Between taking out loans and selling and buying, I've literally spend tens of thousands trying to find the best.
Everything from the mid grade stuff to the highest of highest. I did what Ilya Koshkin does. Built a mount to hold multiple scopes on a tripod and look through them all from one hour before sunset to 1 hour after sunset…as well as sunrise. Into and away from the sun.
This quest ended this year.
Here are some things I can tell you.
1. Manufacturers will lie, deceive, manipulate their numbers. Light transmission, twilight factor, etc.. where and how they measure it, through which lens and through how many lenses etc.
2. I can also tell you that resolution trumps's light transmission. This is where I think most should focus on. I have optics that physically look brighter, but is hard to distinguish what you're looking at compared to optics that don't look as bright, but they resolve so much better that you can see what you're trying to see.
3. Optics with extremely high light transmission generally do horrible with glare or flare, depending on who you talk to on the definition.
So. From the mid grade, I've owned:
Mark 5HD, Trijicon HX, Tenmile, Zeiss V4 and V6, Tract, Leupold VX5 and 6hds, Leica Amplus, Nightforce NX8, Swaro Z6, Maven, Sightron, Steiner T6Xi and HX, Vortex and everything in between.
From the high end, I've owned:
Minox ZP, S&B Ultra Birght, S&B Polar, Leica Magnus in all their mag ranges, NF ATACR, ZCO 4/20, Swaro Z8 3-18, Kahles 318/525's, Zeiss V8 now, Zeiss Diavari, March, etc
My honest opinion. The high end only ever so slightly out do the mid level simple because of the resolution. And it's sooooo minor.
Of the high end, the Kahles, new Zeiss V8, and Minox were the brightest. The Zeiss V8 being the brightest. Contrary to what all the "experts" say, the Polar, Diavari and Z8i fell behind them. But we are struggling to really see differences here.
Of the mid grade, the best to me were the Leica Amplus and yes, the NF NX8 4-32. The NX8 gets a bad wrap for whatever reason, but my 4-5 samples of the NX8 are phenomenal. The Steiner HX and Swaro Z6 were identical to me and both being right at the top.
I'll also say if you covered all the high end optics in this list and threw in the Leica Amplus, you probably wouldn't see a difference between the Amplus and the top tier. It's excellent in low light.
If I had to just pick one mid grade and high end low light optic that was good with glare from the setting or rising sun, resolved great, awesome eyebox, bright etc, it would be the Leica Amplus and the new Zeiss V8 NA.
I'm sure others will disagree with some of this.
I guess what I'm saying is don't get to crazy wrapped up in low light riflescopes here.