For anyone who is interested in older cameras I use a Canon Rebel T3i as a webcam and it works fantastically. In 2020 because of you-know-what Canon released a webcam driver for a bunch of their cameras and the T3i is one of the oldest ones supported (the most recent version of their driver drops support for this camera but older drivers work just fine).
Paired with an AC power adapter and a mount for my monitor it's a nice webcam. I bought a 24mm lens for it that was reasonably affordable and I get a nice "real" bokeh effect in my background (it's not as blurry as the computational one but it's a nice to have). (FWIW I also push it through OBS to crop it).
Mileage varies between cameras, but one small warning to anyone considering this if they spend even a couple of hours a day in meetings with the camera on from time to time - the sensors in some DSLRs/mirrorless models can overheat while live streaming and your video will cut out.
Most of them were only specced to record up to 30 minute clips at a time in original guise and are passively cooled, so running for an hr or more can push the sensors beyond their original specifications etc. I've had this happen rarely with some m43 cameras I use as webcams via an HDMI capture card. There's a ton of youtube videos on this topic with all sorts of homemade cooling setups:
For anyone that might also already have a Nikon D5100 or D7000 to repurpose as a webcam, you can use a custom firmware[1] to clean up the HDMI output, an HDMI capture card and OBS to fix the aspect ratio. That's the setup I use.
I have a canon r6 and I cannot for the life of me get the webcam utility to work. The camera utilities work just fine. I can even remote shoot from my pc. But I have not been able to get the webcam utility to work. The support around fixing it that I have found does not fix the problem, but is always suggested is to turn off the camera utility software but again, I’ve tried that and many other things and can’t seem to crack the code..
how do you use this with an AC power adapter? I have one and I've used it but I run out of battery quickly. is there a way to power the camera with AC??
Most cameras enable using an AC adapter with a dummy battery insert that provides a barrel power jack. A quick search for that for this camera shows that it seems to be the case for this one.
There’s a kind of power cord that has a dummy battery that plugs into the mains. The camera’s battery door also has a hole to run the cable through. Searching for “dummy battery $CAMERA_MODEL” would get you what you want
Paired with an AC power adapter and a mount for my monitor it's a nice webcam. I bought a 24mm lens for it that was reasonably affordable and I get a nice "real" bokeh effect in my background (it's not as blurry as the computational one but it's a nice to have). (FWIW I also push it through OBS to crop it).