Q: Since macos sierra my isight FireWire doesn´t work with Facetime

As a test, try to install Skype, and use iSight as the video source. In my test, Skype works, so all fingers point to FaceTime.

Same problem.

I just tried a Tandberg/Cisco PrecisionHD USB camera - it is several years old but admittedly newer than our old iSights!  Worked perfectly in Quicktime, Photobooth, etc.  It also worked in FaceTime.  So, perhaps the issue is a bug in Sierra FaceTime specifically with respect to the firewire camera input?  Also, I had the same non-functional behavior with two different iSights.

All of that being said, I still couldn't figure out how to get the FaceTime window to show landscape at 720p...

Kraig.

I have the same problem with isight after upgrading, Photo Booth works with video, quicktime displays video, but cashes on record. Also, cannot complete video call, only audio call. External firewire iSight Camera, everything work fine in El Captain.

It works fine on Siri

Same problem, same model computer. iSight Firewire cam and mic works with Skype and QuickTime record.

Mic DOES work with FaceTime and is listed in the preferences for FT audio. No Video setting in the Preferences.

Same problem here. Mac mini 2012 and isight firewire doesn't work on face time.

Clearly this is a bug of some sort. Bug report filed.

Same problem, in my Mac mini (late 2014) the iSight FireWire with Skype is working well only with FaceTime the video doesn't work!