[Henry Sugar]

After more investigation and a very helpful blackmagic support team email, I found out a few things. Consumer level camera hdmi is a touch unreliable, possibly because the signal strength is weaker than pro camera hdmi outputs. It is perfectly normal for the ATEM to have a few seconds connection delay. Blackmagic advise converting to SDI (and back again if all your SDI inputs are already in use, as is the case with me) for a reliable signal.

So far with my cheap cameras I get connection down 1m cables fine. I then added in a signal booster https://www.kenable.co.uk/product_info.php?products_id=1767 (best deal i found) and managed to stretch the signal through a further 3m, 4m now in total. Signal did not make it through a 5m cable, not even using two signal boosters separated by 1m cables near the source.

I am experimenting with using CAT5 cable converters for longer runs… i will post my findings

Henry