[Patrick King]

I’ve just come off the back of a stereoscopic shoot where originally we were going to shoot with two Sony EX3 cameras. The client desired 24p footage, so the cameras were set to NTSC area and HQ1080/24p (actually outputting psf). We tried to genlock the cameras in the way we would if we were shooting PAL – MON OUT of the master camera to GENLOCK IN of the slave. This has been rock solid in the past, at PAL 25p and 50i.

But in NTSC, and at 24p, there was heavy visible distortion to the images of each camera… Clearly not genlocking.

Circumventing the camera to camera route, we fed timecode into an Ambient lock-it box to the EX3s, an took the Trilevel sync out into a Kramer DA and into each cameras GENLOCK IN. No joy.

Then an AJA GEN10 was introduced into the setup, feeding from it to each EX3. Dipswitches were set to the the correct settings (from what info on video standard the camera and display settings on a Transvideo informed us of. Still no stable images from the far-from-genlocked cameras. (Configurations for 23.98 were also tried with each genlock sync generator (the EX3 is actually 23.98p as opposed to 24p).

Running out of options, time for experimentation and patience, we took to the decision to go with Sony P1s. 24p, GEN10, both cameras genlocked.

We had acceptable images, though over a short period of time, the sync would drift. We would check sync before turning over, and if necessary, cycle power on each camera.

My immediate feeling is that 24p/psf doesn’t like being genlocked, although I’m not unconvinced that it’s an issue with power supplies in the UK and 50Hz vs 60Hz phase issues. I will hopefully get the chance to research this in more depth, and will notify of any findings.

Good-luck.

PS: EX3s were run off battery, P1’s off 13.8v power supply.