We use the SDI output (that cable is sturdy and the bnc lock connector is rock solid) and a Blackmagic 12G SDI to HDMI converter, and then an El Gato HDMI capture card.
Intuitively, I’d say most of the delay is coming from the HDMI capture side (it’s a pretty cheap usb dongle).
I measured 40ms, so about 1-2 frames of lag. This was the camera's hdmi output captured with the el gato dongle (whose performance I underestimated..!)
