This is mirroless
Those reviewers who are upset at the CF Express slot are smooth brained mouth breathers. IT SHOOTS 6k RAW. Even the best UHS-II V-90 SD card can't come close to being fast enough for that. It also has a bottomless buffer RAW at 20 fps with a CF Express, your top of the line SD can't do that either. Not to mention a V90 SD card is the same price/GB as a CFexpress B anyways, despite the CF being 5-7 times faster. I wish it had two CFexpress slots.