Hi +Josephine Lee
. I use a "Canon EOS 6D", which is a full frame camera and perfect for this kind of shooting.
The key here is to use a tripod, large aperture (example : F2.8-4) , long exposure time (example : 2-30 sec.) and high iso settings (example: iso 800-6400)
I also use wide angel lenses(14-24mm) with wide aperture to shoot Northern light.
Here is an article that explains it even more:http://www.digitalcameraworld.com/2015/03/22/how-to-photograph-the-northern-lights/
I hope this could help you a bit :-)