ATOMOS makes a range of professional HDMI cables which are ideal for connecting between your camera and NINJA V+. For 4Kp50/60p and RAW recording we advise the use of ATOMOS HDMI 2.0 cables. For more information and to purchase ATOMOS HDMI cables, visit the HDMI Cables page on the ATOMOS website.
In terms of third party HDMI cables, they are not all created equal and there are a variety of different qualities available. Please make sure you test your cables prior to shooting. This is particularly important when recording 4Kp50/60 and RAW. Many cables will claim to be high speed but will lack the required shielding on both cable and connector to maintain a high quality signal. If the signal contains errors that affect your recording, your NINJA V+ may not lock to these inputs.
Take care to use HDMI cables of the appropriate grade and ensure that you protect them from damage. Signal issues can often result from damaged HDMI cables, or from using cables that are too long.
Also check your connectivity at both the camera connector and the recorder / monitor connector to make sure you have a firm connection, to avoid signal drop outs.