Canon C400: checking genlock, reference output and timecode

C400: separate reference, lock and picture

Confirm the model of every camera before applying C400 settings; a similar model name does not establish that its connector or menu works the same way. Record the reference signal and format tested for each camera.

Record the actual firmware, signal levels and full path. Check reference lock and latency separately with the signal planned for the event.

This guide uses the Canon EOS C400 Instruction Manual, file version 1.6, eosc400-im7-en.pdf, PUB. DIE-0587-000G. Its cover identifies firmware 1.0.7.1; the official file listing was updated July 28, 2026. These details identify the document, not the firmware installed on the event camera.

On pp. 110–111, Canon lists analog blackburst and HD tri-level sync as genlock inputs. Those sections do not provide a complete matrix of reference rates against every recording and output setting. The specific 720p59.94, 1080i59.94 or NTSC blackburst combination still needs checking on the actual unit and, if it does not lock, against documentation for that configuration.

Genlock input: connector, wait and indicator

With the camera in CAMERA mode, save the initial configuration and select MENU > System Setup > G-LOCK/SYNC/RET Term. > Genlock Input before connecting the generator. The diagram on p. 110 shows a DIN–BNC cable. The specifications on p. 275identify DIN 1.0/2.3, a 1.0 Vp-p input and 75-ohm impedance for Genlock Input. TIME CODE uses another DIN terminal: check the label, not just the adapter shape.

Canon states on p. 111 that a suitable signal takes approximately ten seconds to stabilize. Buttons and the LCD touchscreen do not respond during this process. Wait and watch the Gen. indicator at the top right: it flashes when a suitable reference is detected and stays on when the camera locks. That expected pause alone is not evidence that the camera has frozen.

If the indicator does not appear or stay on, record what it does and trace the reference path: terminal function, generator output, cable and adapter. Off air, compare a verified output and cable, changing one variable at a time. Record the complete reference format and observed time; an SDI picture does not confirm that this input receives a suitable signal.

Genlock Adjustment > Change changes horizontal phase. Canon describes approximately ±0.4 H, with Reset returning to [000]; the table on p. 228 lists –1023 to +1023, default 0. Record the setting before changing it, and adjust it only for a defined, measured alignment. It does not replace checking the signal when the camera will not lock.

The C400 input is specified at 75 ohms. Do not apply the passive Ref Loop procedure for an FS4 to the camera or add another termination by habit. If a distributor or chain is involved, identify every connection and consult that device's manual.

Canon warns that an incorrect reference can make synchronization unstable and affect recorded timecode. Check rehearsal clips as well; the indicator does not replace checking the recorded material.

HD Sync Output uses the same terminal as an output

To send reference from the C400, p. 112 specifies System Setup > G-LOCK/SYNC/RET Term. > HD Sync Output. The signal is HD tri-level sync; its configuration depends on SDI OUT and other menu settings. Where applicable, select SYNC Scan Mode > P or PsF. Record those settings and what the receiver accepts before connecting the cable.

Genlock Input and HD Sync Output are alternative functions of the same terminal. If the camera is meant to follow an external generator, check that it has not been set as the reference source instead. Draw the direction of each run before connecting two devices.

P and PsF are documented reference-output options here; they are not a recipe for making any input reference lock. Do not infer the reference sent solely from the codec or clip resolution. Keep the SDI OUT configuration recorded and check the signal at the destination.

The menu also offers RET Input. Do not confuse it with Genlock Input: the selected function changes what the terminal does. This guide does not configure return video or prescribe its routes; those need separate checks.

TIME CODE: synchronized LTC does not confirm genlock

Canon separates the paths on p. 110: G-LOCK/SYNC/RET receives reference to synchronize the video H and V phases; TIME CODE receives SMPTE LTC to synchronize the counter. For LTC input, select System Setup > TC In/Out > In and Free Run timecode mode before connecting. User Bit Recording Mode > External lets you record the external user bit when needed.

The note on p. 110 specifies 24-frame LTC for 23.98P or 24.00P, 25-frame LTC for 25.00P, 50.00i or 50.00P, and 30-frame LTC for other rates. Keep DF/NDF in view as well: p. 111 says that, when receiving external timecode, this selection follows the source. This is an LTC rule, not a genlock signal table.

After receiving suitable LTC, Canon keeps the counter synchronized when TIME CODE is disconnected. Without that cable, cycling power, entering MEDIA or changing video configuration breaks synchronization; reconnecting restores it. If pre-recording is enabled, Canon warns that incoming external LTC can introduce a discontinuity in the pre-recorded clip. Check these points after a configuration change.

To send LTC, select TC In/Out > Out. Canon says timecode and user bit are not output when slow & fast motion, frame recording or interval recording is active; in MEDIA, user bit is also absent from TIME CODE. If a receiver gets nothing, record those functions and terminal direction first.

During planning, note whether each camera, recorder, computer and LED processor needs reference, timecode or both, with the connector and parameters for its model. Check other devices' compatibility and PoE power requirements against their own manuals; they cannot be inferred from C400 documentation.

Record the test and check the other multicamera paths

Use the blank C400 reference and LTC worksheetto record firmware, formats, terminal function and each comparison result. Keep proposed tests separate from completed ones and attach evidence if you perform the rehearsal. This guide contains no GLMedia physical test results.

If the generator is a GEN10, use the group and DIP-switch guide. For a processor in the rack, see FS4: format, audio and sync; its states and termination apply to the FS4, not the camera.

For a conference with LED, recording and streaming, check each destination after synchronizing the sources. Plan video processing and distribution around those paths and formats. The genlock indicator alone does not promise lower latency or an artifact-free picture.