capturing standard def via firewire on a mac

Figured someone might find this useful.  A client recently purchased a refurbished 2017 macbookpro which only has usb-c/thunderbolt ports.  She wanted to capture some hi-8 tapes.  She has a sony hi-8 camera which does not have a firewire output but has composite and svideo outputs.  She also has an sony hdv deck which has svideo input and firewire out.  And she has a blackmagic intensity usb3 device.  

The macbookpro came with high sierra installed.  I wanted to be able to run premiere 2021 on it, so did the simplest thing which was to update to big sur.  Unfortunately Blackmagic does not support the instensity usb3 device anymore so I had to revert to hi sierra and then update to mojave (apple does not make these things easy - if anyone needs instructions on how to do this - post back and I'll walk you thru it) in order to find a version of the blackmagic desktop video utility that would work with the intensity.   If anyone wants the correct version number of the blackmagic desktop video utility, post back and I'll figure it out.  Spent a few hours walking back thru the versions til I found the one that works.  But gotta say Blackmagic doesn't throw any unnecessary barriers to finding and installing the earlier versions.  

And then discovered that the output of of the hi-8 camera was not stable video and would not work with the intensity.  running the hi-8 output via s-video to the hdv deck stabilized the video (I'm guessing the hdv deck has some sort of tbc built in) but the hdv deck does not have composite or svideo output, but does have firewire.  So, got the apple firewire to thunderbolt 2 adapter....  which of course does not plug into the usbc/thunderbolt ports on the macbookpro.  Then got what apple calls the thunderbolt 3 adapter to thunderbolt 2 (although in my head it should be called a thunderbolt 2 to 3 adapter, bwdik) and tried to capture in Premiere 2021.  Didn't work.  Installed Premiere 2018 (which adobe does not make easy - anyone who needs help with this post back...) and everything is working.  

Not simple, but did get everything working.   Took about a week of intermittent concentration and the client was suitably impressed.  When I get back to her studio, will update the bootable clone from the macbookpro so we'll have back up for this setup in case we need to update something else and lose this capability...  

Haven't had a chance to test HDV capture, but I imagine it will work.  Will test it somepoint soon.