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Toggling between webcam and screen shares in Zoom can be a little confusing - this page is designed for tips for managing smoother transitions.
Getting started with Screen sharing in Zoom
Toggling to a "New Share"
Instead of clicking "Stop Share" and then having to start over with new one, you can use the "New Share" option for a more smooth transition to your new shared window or device
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To share a Document Camera (doc cam)
After clicking "Share" or "New Share," Click "Advanced", and then click "Content from 2nd Camera".
See Screenshot below.
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Sharing an iPhone screen, or video & audio