So my 5D Mk3 started to not turn on once in a while and I took it into Canon Professional Services - I asked if they could leave firmware version untouched and they said now step one in any service is to upgrade firmware. Needless to say I now have 1.3.3 firmware installed and looks like no ML will run on that. I have a Canon EOS 5d Mk II and 5d Mk III. Both worked well with Tethered Catpure until these OS and LR upgrades, and now when I start Tethered Capture, it doesn't recognize the camera. I checked connections, restarted and reconnected the camera, restarted the computer, deleted Lighroom Preferences, updated my camera firmware. Canon HDMI Camera Settings - Canon 1DC/ 5DMKII This section applies to the Canon 5D Mark III (firmware v1.2.3) and Canon 1DC (firmware v1.3.5). Please note that though the Canon 1DC can record 4K internally, the output is HD only. 1. SET CAMERA TO VIDEO MODE 2. SET INTERNAL RECORDING My 5D mark III (bought new in Japan, but has been updated to firmware 1.2.1 from the US) can be changed to French, German, Swedish, Danish (which I would claim is far more important than Swedish ) etc without any limitations - my 5D mark II (bought second hand in Japan, and never updated with a non-Japanese firmware) can do the same, in fact Uncompressed HDMI output is now enabled. 2. Enables the center AF point to autofocus when the camera is used with Canon EF lens/extender combinations whose combined maximum aperture is f/8. 3. Improves the speed of the camera's acquisition of focus when using a Canon Speedlite's AF-assist beam. Auto Focus Configuration Tool Preset: Case 4 (on Canon cameras), but sometimes I switch back to Case 1 if I feel like I’m having a bad focus day and I want to blame it on the equipment instead of the real problem. Highlight Warning: On. Lenses: Main camera: Day game: 200-400mm f/4 Main camera: Night game: 400mm f/2.8 (to keep ISO lower) Customers who own an affected unit and wish to have it updated to Firmware Version 1.3.9 are able to bring their cameras to their nearest service or repair centers or may perform the update themselves by following the instructions contained within the following firmware update files: EOS 5D Mark III Firmware Version 1.3.3 [Mac OS X] Canon 5D Mark III is a really lovely daytime photography camera. Many members here have done really nice Astro work with cameras much worse than your Canon 80D which should get you really nice images if you mod it. I would keep the 5D Mark III for daytime use. If you want a better camera still for Astro, I would look at Astro specific cooled 9LIcku.