During a night dive on the reef flat, the swell was flopping the sea fan back and forth, and I was swaying as well.

So I turned upside down to keep my fins from damaging the reef and tried to pre-focus manually. Then it was just a matter of composing the image and waiting till the fan moved them into focus. It took about 8 or nine tries before I got an image I thought was probably sharp.

I never saw these nudibranchs during the day.