How important is it to match cameras (make and model) on multi-camera shoots? Like everything in production, that depends on your end goal. Generally speaking, you always want to match not only brand (make), but also the model of camera. There are differences for instance, between the image produced by a Sony FS7 MkII and a Sony a7S II, but it’s not a huge difference. You could dive into the specs of the processors, image sensors, color space, etc., but when push comes to shove, they’re very similar. Let us hypothesize a few scenarios:
Two-subject, three-camera interview. Budget is always the driving factor in production. Using a DSLR as your lock-off wide shot for a two or three person interview is great. You can easily match shooting specs, and shoot without a color profile. Additionally, run audio to your nicer cameras capturing the singles, and you’re great.
Event coverage with interviews. If you have the budget to have a Sony FS7, Canon C300 MkII, or similar, you want to take advantage. However, getting smooth gimbal or slider shots is much easier with a DSLR and Ronin-S or Cinevate Duzi (think small and light). The b-roll that you’re using to compliment your interviews will look great as long as you’re matching camera makes (Canon with Canon, etc.)
Different cameras, same assignments. If you have two crews capturing similar content, but using different brands of cameras. The common viewer may not notice, but an experienced client probably will.
All in all, while the world won’t end if you mix camera brands or models… life will be easier if you don’t.