Going into huge detail about these two cameras, their physical characteristics and features, buttons, batteries, sizes.

I rented the Sony at https://share.lensrentals.com/x/BusIq7 you can support my channel if you follow this link and you'll save yourself $25 your next rental.

You can find these cameras on Amazon: Sony A9: https://amzn.to/2P534eD

Canon 1Dx Mark II, they don't have III yet: https://amzn.to/39Jrz8X

If you want Mirrorless A9 II is impossible to beat at the moment, for DSLR, go with 1dx. If you own lenses for either, then just go with what lenses you have. Both create amazing images.