It’s very much about the preamp in this situation. A really good preamp has a lot of good gain.
The better the preamp, the more clean gain, especially at higher gain levels. Cheap preamps get noisy (in addition to being louder) as you turn them up.
Camera preamps are OK. Cheap mixers may be OK, but the price frequently means they are not.
Sound Devices makes the MM1, a plain preamp that’s nice. They also make the MixPre; a quality little mixer with the exception that it has a line level output. If your camera only has mic level inputs, they sell a set of adapter cables that reduce the line level to mic level. It also has an unbalanced stereo output that you can plug in to the little prosumer cameras.
Mark McQuilken’s RNP preamp is an exception. It requires AC, but it’s a nice little preamp.
Preamps and mixers are different. I mention this here because some folks have bought preamps thinking that they will save a few dollars, only to find they bought the wrong thing. You find preamps IN mixers, but not mixers in preamps.
Preamps usually have only one output. Mixers have several preamps (inputs) and an output stage that allows the input to be routed to different places including a master stereo output.
Mixers are also usually designed to be adjusted on the fly, allowing the user to ride gain during recording. All of these things can make a big difference in the quality of the recording.
Regards,
Ty Ford
Want better production audio?: https://home.comcast.net/~tyreeford/AudioBootcamp.html
Watch Ty play guitar: https://www.youtube.com/watch?v=4RZJ9MptZmU