In 2019 Nikon has started shipping Z series lightweight mirrorless cameras based on a significantly larger opening for light transmission and corresponding Z mount lenses featuring about twice as much light transmission as classical F mount optics. Z series uses predominantly full frame sensors up to 46 Mpixels.
Only Z50 uses 21 Mpixel APS-C type sensor, crop factor 1.5. This lower priced but fairly good and stirdy camera is ideal for lightweight bird photography. It supports both TX-14E and TX-20E Z Series teleconverters providing you with up to 1500mm 35mm equivalent using for instance Nikkor 500mm f/5.6E PF VR. All Z camera’s use an advanced multipoint AF system and high resolution electronic viewfinder (EVF) featuring extremely clear sharp image.
Z5, Z6 and Z7 are full frame MLC’s.
More detail at Camera’s.