Twin J1's, stereo 3D images
With the J1's being sold at fire sale prices, I picked up two, and use them for stereo photography.
The only way to trigger both at the same time is to use the IR remote. Still, they sometimes go off at slightly different timings, in both AF-S and AF-C mode. Not sure how this can be helped.
By using the Movie mode, the remote triggers the start of the video recording, which appears to be more consistent in terms of timing.
Anyway, I have some example images and video, and a description of the setup here: