Vision Systems and Screen Operations
The vision chain
Vision systems follow a chain: camera/source → signal transport → switching → processing → display. Know the common signal types (SDI, HDMI, and IP-based video over network) and their limits - cable length, bandwidth, and resolution. Understand resolution and aspect ratio (16:9, 4:3) and why mismatches cause letterboxing or stretching.
Switching and display
Video switchers mix sources, key graphics, and output to screens or projectors. Know the difference between a program (main) output and preview/multiview. LED screens are built from panels with pixel pitch affecting viewing distance; projection depends on throw distance, brightness (lumens), and ambient light.
Operation and safety
Operators run cue lists, manage source changes, and coordinate with lighting and audio. Cable runs must be secure and within signal limits; long HDMI runs often need extenders. Screens must be rigged and earthed safely, and power loads calculated.
Traps
Questions often test signal conversion - HDMI to SDI requires a converter, not a passive cable. Another trap is confusing program with preview, or assuming any cable length works. Beware options that ignore aspect ratio or pixel pitch.
Worked example
A laptop (HDMI) must feed a switcher 30 m away. HDMI over 30 m is unreliable, so convert to SDI and run coax, then convert back at the switcher. Always plan conversion at both ends.
Rule of thumb
Match the signal to the distance: short runs tolerate consumer formats, long runs need professional transport.