I just used a Tricaster Mini in a system that has 3 Panasonic PTZ cameras going through a managed switch in an auditorium. the run to the control room is about 150 ft. I added 2 cameras on the stage: 1 went via SDI and the other was a GoPro which went to an HDMI Spark and ran through the same switch as the PTZ cameras to the Mini. it showed up in the switcher right away, but it showed a clear latency compared to the other cameras - it was on the drummer so very easy to spot. I'm wondering why the Spark would cause a latency more than the cameras with built-in NDI. I used to send the drummer GoPro through an HDMI-SDI converter and that did not show latency.