Northern Lights

[HL45]

I packed light, and was considering not bringing my camera (haven't seen northern lights before, so I was afraid bring the camera might scare it away)

 

[apaflo]

I shoot wide open pretty much all the time when shooting at night. Shooting at f2.8 is pretty much the norm for astrophotography.

But this isn't astrophotography! Considering the chances anyone asking questions about photographing aurora is likely to be using a kit lens (which in this case turns out to be true), the advice about stopping down is appropriate. It also happens that, even with a really good high quality f/2.8 or better lens, it would still be good advice for auora photography simply because there is no reason to use the lens wide open. There just is nothing to be gained!

It turns out the 18-105mm kit lens used is not too bad wide open at short focal lengths. But it absolutely is sharper when stopped down. The camera can easily shoot at ISO 400 or 800, so the same image could have been obtained at f/8 rather than f/4, using ISO 400 rather than 100. A better solution might also have included going to ISO 800 and using 15 seconds for the shutter speed rather than 30s, though if the auoral display was fairly static with no movement that might not be an improvement.

Incidentally, I would not use 18mm either, but would zoom to a slight bit more focal length just to get away from the end of the zoom range. It probably wouldn't need to be all the way to 24mm, but at 24mm the maximum aperture is f/4, so stopping down 2 full stops would be f/8. One could shoot a few shots at f/5.6 and a few others at f/8, and then later pick out the best results.