Select Enable to enable the electronic front-curtain shutter in Mup mode, eliminating blur caused by shutter motion.
A mechanical shutter is used in other release modes.

The Electronic Front-Curtain Shutter

A type G, E, or D lens is recommended; select Disable if you notice lines or fog when shooting with other lenses. The fastest shutter speed and maximum ISO sensitivity available with the electronic front-curtain shutter are 1/2000 s and ISO 51200, respectively. The electronic front-curtain shutter cannot be used with the ML-L3 remote control.