Note that the S1 offers an Auto shutter mode which switches the shutter type to suit the recording conditions and shutter speed, but it defaults to mechanical shutter. Using the Electronic Front Curtain Shutter (EFCS) mode produced slightly faster results, while the fully electronic shutter option increased shutter lag slightly. Shutter lag in manual focus mode was very low at only 0.067 second, and prefocused shutter lag was lower at 0.060 second. That's competitive with a lot of pro DSLRs.
In the lab, the S1 produced a full-autofocus shutter lag (with the subject at a fixed distance) of 0.154 second using 1-area (center) AFS mode with the Panasonic Lumix S Pro 50mm f/1.4 lens using default mechanical shutter mode. The Panasonic S1's autofocus speeds were quite good in our tests, especially for a camera that uses contrast-detect AF. Note: All timing performed with a Panasonic Lumix S Pro 50mm f/1.4 L-mount lens.