The small form factor of the Elphel 353 cameras make them very versatile for shooting 3D. In a side-by-side configuration, a minimum inter-axial distance of approx. 45mm can be achived. The small cameras would also be well suited to an on-the-shoulder beam splitter rig.

Nathan's Apertus3D Rig

Side-by-side + shooting parallel (rather than toe-in)

Sync

Shooting Apertus S3D footage is possible by synchronising the sensors read out phase on the two cameras (to do this, the 10369 board is required on both cameras). There is one master camera that generates the trigger impulses and therefore defines the recording frame-rate. A special connector on the side of the camera is used as SYNC interface. You connect the slave cameras and the master cameras sync port with a cable and in software you make sure that the master camera outputs the sync impulses and the slave camera waits for them to start frame read out.
The sync impulse is sent for EVERY single frame.
This way the start time of the frame read out from the CMOS sensor is kept 100% in sync between all cameras (you can also have multiple slave cameras) at all times.

Syncing of camera parameters like whitebalance, exposure time, etc is handled by the viewfinder software ElphelVision.

In-camera HIT

When shooting 3D (with parallel cameras), the screen plane converges at infinity - meaning everything comes out of the screen (in a very bad way). This method of shooting requires that the footage is shifted horizontally in post, to determine a comfortable convergence point. This shift is called Horizontal Image Translation (H.I.T.) and invariably results in the loss of horizontal resolution.

Since Apertus is using an oversized sensor with region of interest (ROI)- It is possible to perform the HIT in camera, by shifting the ROI horizontally across the sensor. This way you are converging in camera and do not need to do so in post - as such, there is no loss of horizontal resolution!

Software

StereoCamCheck

A special software is being developed that can display 2 real time video stream in different viewing modes like  side-by-side, anaglyph overlay. Realtime GPU debayering of JP4 Raw video streams has also been implemented.

ElphelVision

Even though the sensors are synchronised, a further challenge was synchronising the record start time for both the left and right clips. To achieve this ElphelVision is setting a record delay time therefore tells the cameras to start recording at a specific time, several seconds into the future (based off the master camera's timecode). This way, the first frame of both the left and right clip are temporally aligned.

Clips are recorded to each camera's own hard drive and are placed in a timecode stamped folder, unique to each clip. ElphelVision provides the ability to append a custom name to these clip folders, so footage from the left and right cameras can be named appropriately and automatically.

It is possible to switch between viewing each video stream within the main GUI. It is also possible to disable the live stream altogether (useful for using additional preview software, such as StereoCamCheck)