Exposure & Flash Time and Marker Threshold

To finish achieving the right balance of light, adjust Exposure & Flash Time and Marker Threshold.

Exposure & Flash Time is the number of microseconds that a camera’s shutter stays open—typically between 100 and 300 microseconds. Shorter exposure times let in less light, while longer times let in more.

Marker threshold sets the intensity of light that QTM interprets as a marker. This is usually set between 20 and 50%. Lower values make it easier to view markers but also more likely to pick up unwanted reflections.

The two settings often impact each other and should be changed together for each camera.

Switching QTM to intensity mode can provide visual cues as you go. You should aim for a dark background with the markers clearly displayed in red.

If the markers are not visible enough, try increasing exposure time to let in more light and decreasing the marker threshold to interpret more light sources as markers.

Conversely, if too many reflections are coming through, try decreasing the exposure time and increasing the marker threshold.

 

Once you are satisfied with your camera settings, remove the reference markers and switch to marker mode to confirm that no reflections are being picked up in QTM.

If you still have unwanted reflections that you couldn't resolve through the camera settings, you may be able to remove them through exposure delay or marker masks as shown in the following chapters.