DSLRs & mirrorless camera internal microphones are pretty much useless. They also have notoriously bad preamps when using external microhpones. No matter how good a microphone you plug into it, when you bump up the record level on your camera, you add noise. Lots of it. The typical solution to this is record to an external unit, like the Tascam DR-70D, and then feed a line from your recorder into your camera to make it easy to sync up in post.
But what if you could skip the external recorder and actually get decent quality inside the camera to begin with? Well, Caleb Pike at DSLR Video Shooter has the answer. A $23 adapter for using your microphones with your cellphone. In this case, that adapter is the Saramonic SmartRig. Caleb offers two ways to use SmartRig to get quality audio into your camera.