SmartFocus automatically zooms in on an area in a Camtasia recording file (.cmrec) based on the activity within the recording. When recording, Camtasia collects data about the actions completed and the cursor movement in the recording. The SmartFocus at Time action predicts where to add zoom effects, saving you the time it takes to manually find and insert actions.
SmartFocus at time can only be applied to Camtasia recording files (.cmrec).
Add a SmartFocus at time:
Click the Video Effects tab 
.
Position the playhead to the location you want to zoom in on.
Drag the SmartFocus at Time action onto the timeline where the endpoint is in line with the playhead or press Command-Control-A. 
Camtasia zooms in on the activity within the Camtasia recording.
Edit a SmartFocus at time action:
To adjust the zoom duration, drag the action’s endpoint to adjust the zoom duration.
To adjust the position, drag the video clip on the canvas.
To adjust the zoom scale, click and drag the clip’s handles on the canvas. Any canvas changes apply to the red line area, from the endpoint until the next SmartFocus action or the end of the clip.