Why are my photographs always underexposed?

Why are my photographs always underexposed?

So, you get your Retra Flash and are super excited to try it out. You go on a dive and take some great shots, but when you review your photographs they're all severely underexposed or even black... 

If your photographs keep turning out underexposed, then keep reading to find out how you can troubleshoot your Retra Flash and resolve this issue.


First, you can try running this diagnostics test to pinpoint the actual issue.

Complete the steps below and review the results:

  1. Connect the Retra Flash to your camera housing
  2. Set the Retra Flash to M (Manual mode) and turn the power dial to 100
  3. Trigger your camera and check the results

If the Retra Flash was not triggered, please double-check that the optical connector is installed correctly and try again.

If the Retra Flash was triggered successfully and the photograph comes out under-exposed or black, please follow one of the solutions provided below.

Set Retra Flash, Camera & Housing Trigger to compatible modes

Please refer to the user guide for the trigger board and camera for instructions on configuring settings to emit a single pulse (manual mode).

Adjust the trigger board and camera settings to generate a single pulse (manual mode).

Turn the mode dial on the Retra Flash to M (Manual) and set the power dial to 100.

Try the diagnostics test once again to see if the issue persists.

Set the Retra Flash to SSL mode

If your camera emits only TTL light with pre-flash(es), and you wish to set the Retra Flash with manual exposure, you can use the SSL mode - Smart Slave Mode (default position - U, U2) on the Retra Flash.

The Smart SL mode will automatically detect a TTL signal and the number of pre-flashes and ignore them. The SL mode detects and ignores from 1 up to 10 pre-flashes.

Please note that every time you enter mode "U" or "U2", the Retra Flash will first go through a calibration process.

Calibration procedure:

1. Retra Flash Pro Max: Follow on-screen instructions / Other Retra Flash models: Follow instructions below

2. A pulsating light will appear, indicating the Retra Flash is ready

3. Trigger the camera once and wait for 2 seconds

4. If the light stops flashing, the Retra Flash has been calibrated and will fire with manual power settings (same as in M - manual mode)

5. If the light keeps flashing, please exit the "U" mode and try again


If your photographs still come out under-exposed or black after trying the steps in this article, please do not hesitate to contact us at help@retra-uwt.com, or reach out via Whatsapp, Viber, iMessage or our social media.

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