I put together a short clip with the new Nikon D5300 showing its high ISO performance at night in the misty, foggy Budapest winter.
I think at ISO1600 quality is acceptable, but I wouldn't go higher...
I didn't have a video head, so there are only static and handheld shots. Also I didn't have prime lenses with bigger aperture like 1.8 or 1.4, so I used my -otherwise great - zooms at mostly f2.8, so some scenes are pretty underexposed.

Equipment used:
Nikon D5300,
Nikon 24-70/ 2.8
Nikon 70-200/ 2.8 VR

Tripod with no videohead, some shots are handheld
ISO: 800-1600,
Shutter speed: 1/30-1/50, Aperture: 2.8-3.5
NO post processing : contrast, color correction, sharpening, noise reduction, etc.
( Some clips are slowed down in Premiere )
Camera color scheme setting: standard
Fast clips are made by in-camera effect preset

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