Most consumer-level Macs include a built-in iSight camera. On these computers it is not obvious how to use an external camera, as the OS assumes you want to use the iSight.
To use an external camera, launch Logger Pro and insert a video capture object. Logger Pro will use the iSight. Click the Options button, and then the Camera Settings button. Click the Source tab. There you can choose to use the Proscope or other external camera, as long as the drivers for that camera are present.
These instructions are written for OS 10.4.9 and work on an Intel-based Mac. Details may be different for other versions of the OS.
For Intel-based Macs using OS 10.6 or later:
To use an external camera, launch Logger Pro and insert a video capture object. Logger Pro will use the iSight. From the Capture Device Settings, click on the Video Input pull down and select the Proscope HR or other external camera, as long as the drivers for that camera are present.
Logger Pro cannot see internal iSight camera on Mac running 10.8.5