In this video I’m looking specifically at high ISO / low light performance on the Leica Q3 Monochrom, and I’m putting it side-by-side against what I consider the best of the color-sensor class for this kind of test: the Fujifilm GFX100RF converted to black and white. This is not a full review or first impression—my time with the Q3 Monochrom is still short—but I wanted to answer the big question: does a dedicated monochrome sensor actually matter when you’re shooting in the dark? I walk through real-world comparisons at ISO 3,200, 6,400, and then jump to the extreme end at ISO 25,000 (25,600 on the GFX). At 3,200 they’re surprisingly close: I’d give the GFX a tiny resolution edge, while the Q3 Monochrom has slightly cleaner darkest shadows. By 6,400, the GFX still looks sharp in brighter areas, but in deep shadows it starts losing fine low-contrast detail, while the Leica hangs onto it. At ISO 25,000+ it becomes obvious: the Q3 Monochrom “blows the GFX away” in noise and, more importantly, retained detail in dark regions. I also show a usable ISO 50,000 shot (with IBIS helping) where the noise looks organic—something I just don’t see happening on a typical color sensor.