Here are the suggestions from great photographers I’ve found:
Hobart auroa photographer Loic Le Guilly suggests 30 second exposure at 3200 iso, 16mm rectilinear lens wide open at f2.8.
Local Geelong photographer Lachlan Manley exposes for 20-25 seconds at Iso’s 100-2500. Several shots have roving flash highlights to pick out built features.
OK when you have found the perfect Aurora on the perfect night your going to try a hew shots. Pretty obvious, but step 1 is setting up a triopd. Step 2 is working out how to activate the shutter without moving the camera. There are remote shutter triggers for most SLR cameras. ANd some will be able to be activated with a phone app. From past experience, If tour using a light tripod – tying a brick or rock to the base can really help. Worth the effort if your taking multiple pics to compile into a video.
The actual exposure is trial and error. Because digital cameras have a decent preview, you will get multiple stabs at this.
I am going to learn through trial and error on dark nights taking trial pics of the milky way. I will try a variety of iso speeds to test the limits of grain on my photos. I will try a variety of shutter speeds and serioust consider buying a f2.8 wide angle lens and decent flash for the built highlights. Even see if auto exposure works.