Tim Dashwood
February 4th, 2011, 11:15 AM
I recently shot a series in 3D using a HM700 and HM790 paired together for the 3D rig. The method I used would also work just fine for a multiple camera shoot so I've posted this here instead of the 3D forum.
The HM790 has the ability to genlock to a blackburst or tri-sync signal. However, I simply used a BNC cable and took the "Y" out of the HM700 and fed it into the Genlock in on the HM790. The 790 shows "SYNC LOCKING" for a couple seconds and then you have sync. This is very important if you are using a switcher or 3D muxer.
The sync lock worked great in 1080i60, 720p60 and 1080p25, however there is one caveat with 1080p24 (or 720p24.) With 3D, shutter sync is equally important or there will be a temporal disparity between the eyes. This isn't an issue in 25p, 60i or 60p modes but I found that in 24p mode it was simple luck whether the pulldown pattern started on the same frame. We would have to plug and unplug the genlock a few times until we happened to get perfect 2:3 pulldown sync. In the end we decided it was simpler to just shoot the series in 1080p25 because it was foolproof and our first broadcasters are European anyway.
We will conform the masters to 24p later. They will be a little longer but it is always easy to cut out some content.
I also built a single button trigger system using a couple 8-pin remote connectors wired to a DPST momentary switch (pins E & F for trigger.) Fujinon and Canon lenses use the same pins for start/stop trigger.
The HM790 has the ability to genlock to a blackburst or tri-sync signal. However, I simply used a BNC cable and took the "Y" out of the HM700 and fed it into the Genlock in on the HM790. The 790 shows "SYNC LOCKING" for a couple seconds and then you have sync. This is very important if you are using a switcher or 3D muxer.
The sync lock worked great in 1080i60, 720p60 and 1080p25, however there is one caveat with 1080p24 (or 720p24.) With 3D, shutter sync is equally important or there will be a temporal disparity between the eyes. This isn't an issue in 25p, 60i or 60p modes but I found that in 24p mode it was simple luck whether the pulldown pattern started on the same frame. We would have to plug and unplug the genlock a few times until we happened to get perfect 2:3 pulldown sync. In the end we decided it was simpler to just shoot the series in 1080p25 because it was foolproof and our first broadcasters are European anyway.
We will conform the masters to 24p later. They will be a little longer but it is always easy to cut out some content.
I also built a single button trigger system using a couple 8-pin remote connectors wired to a DPST momentary switch (pins E & F for trigger.) Fujinon and Canon lenses use the same pins for start/stop trigger.