Nikon has opened up to TechRadar about why they got rid of the mechanical shutter in the new Nikon Z9 and why it only features an electronic shutter. It seems like a strange move when Nikon has typically had the best and most reliable shutters over the years (with the fastest flash sync speeds), especially when Nikon’s not-a-flagship EOS R3 still utilises one. Essentially it boils down to new faster sensor technology.
Historically, electronic shutters on CMOS sensors have been plagued with one big issue; Rolling shutter. In a chat with TechRadar, Nikon said that an electronic shutter typically takes around 1/200th of a second for a full-frame sensor to read the entire scene. This is a long time in photographic terms. The Z9 sensor’s scan rate, they say, is 12x faster allowing for readouts faster than mechanical shutters.