Nikon Z 6 with 24-70mm f/4 lens + mount adapter
For slightly over your budget, there is the brand new Nikon Z 6. With a full-frame 24.5MP back-illuminated CMOS sensor this Nikon delivers excellent results in low light and can shoot 4K at 30fps (with full pixel readout) and Full HD at 120fps. With the mount adapter you have access to Nikon’s range of FX lenses, and 5-axis in-body IS as well as a new, highly accurate autofocus system, making the Z 6 one to consider.
Excellent low-light performance with 24.5MP full-frame sensor Access via mount adapter to a wide range of lenses 5-axis in-body IS and new focal-plane phase-detection AF