[jofer]

Regular cameras respond to a wide range of wavelenghts, and they do actually reasonably mimic the response of the human eye.

Either way, it's the "range" vs "single wavelength" that's key here. The green band (or blue band or red band) isn't one wavelength. It's an average over a fairly broad range. Single-wavelength (or very narrow range) images are quite different.

[ccgreg]

Take a photo of the sun setting behind clouds, and then marvel that the camera still sees a big red Sun, when your eye barely sees it. That's because the camera goes way farther into the red than your eye, and the clouds let that sub-red through.

[pfdietz]

A fun example of these effects is "black fire".

https://www.youtube.com/watch?v=F0LWtieip9E