While l only shot for 20 minutes or so with the camera, the AF feels very accurate, even when shooting at high-speed. For those unfamiliar with the pellicle mirror system, it has an advantage of DSLRs because the mirror doesn't flap up and down during shooting, so it doesn't interfere with the AF operation. At the same time, the dedicated AF sensor gives it an advantage over typical mirrorless cameras, which typically rely solely on contrast AF and phase detection AF pixels built into the sensor. In short, the A99 feels very similar to shooting with a pro DSLR like the Nikon D5 or the Canon 1D X Mark II. It has the same kind of machine gun feel in high-speed mode and almost-instant lock when you half-press the shutter.