External iSight camera with M1 Mac? I'm attempting to use a 2003-era external Apple iSight Camera with an M1 Mac mini via adapters:

iSight &gt; FireWire 400 &gt; FireWire 800 &gt; Thunderbolt 2 &gt; Thunderbolt 3

This same adapter chain works for video on a 2019 Intel MacBook Pro running macOS 10.15.6 Catalina. Audio required an additional fix, but is now also working on Intel.
On a new Apple Silicon M1 Mac mini, the video webcam does not seem to work. When first plugged in, it makes an autofocus sound and the green light turns on briefly.
Photo Booth is black and says:

There is no connected camera.

The FireWire Bus device is recognized by the M1 Mac's System Information:

Are there known FireWire support issues for either M1 Macs or macOS 11 Big Sur?
How can I use this iSight video webcam with my M1 Mac?

Links:

https://forums.macrumors.com/threads/2272444/
https://discussions.apple.com/thread/252048140


Apple Bug Report:

External iSight FireWire Camera does not work on Apple Silicon
FB9029863
I too get the same results as you are getting. Works on my 2017 27&quot; iMac but no audio.
This video indicates that the iSight camera needs to be updated to Firmware 1.0.3 for the audio to work properly.
For the updater you would need an older Mac. I have an old PowerPC G5 but have not hook it up to see if the updater would work on it but I plan to try it soon.

How to update external iSight firmware?
External iSight microphone audio not working

I did see on one of Apple's pages that it indicated an external iSight will work with Big Sur. No confirmation if it includes Big Sur.
It doesn't work at all on my M1 Mini but system info can see it so that to me indicates the connection is good.
When I called to ask Apple about it the person wasn't of any help. They actually had not heard of an iSight camera, internal or external, before. The best they could do was get provide the link to the updater.