Like Steve said, it takes a low F-stop to work in low light situations. On average, a F2.8 lens, 3000-5000 iso and 1/125th on shutter speed works beautifully. The real trick though is that you'll need to use some type of strobe to get clean images. If you're considering DSLR, the t6 ($450), 1.8 50mm lens ($100) and a $60, 500-series yongnuo speedlight will get you some really clean, great-looking images. As for point-and-shoot, I wouldn't bother. An iphone 6 or 7 will likely get you better overall shots but keep in mind that you're working without flash (the little flash on the camera isn't good at longer distances) so you're always going to be fighting grainy, dark images. Back on the DSLR, I just bought a practically new T1i for $125 off craigslist. For less than $300, you could be setup with the lens/speedlight combo I mentioned and it would get very good shots. If you wanted to go with a variable-length lense, the Sigma F2.8, 24-70mm is excellent and runs $750. BTW, one trick to keep in min for dance floor shots, 1/125th on shutter speed is usually fine for dance shots. Also, on the speedlight, I tend to run mine at 1/32nd or 1/64th power and with a diffusor or bounce-card. It puts enough light out to get the image clean, but you still keep a lot of the ambiance of the space and without hot-spots in the field of flash.