12Apostles sea stacks 4 min exposure

I had been seeking a ‘look’ to set my images apart from everyone else’s and when the wind came up and the clouds rolled in the streaky cloud idea sprang to mind, ie using a long exposure to blur the motion of clouds; giving a strong, in my view, aesthetic feel to the image. I hadn’t tried this before and the questions I had were:

  • what exposure times would be required
  • could this be achieved in daylight

The 2 sea stacks form a perfect foreground for this and the high wind and scattered clouds make for good conditions to try it out.

First, a daylight attempt.

Even with an ND400 filter (about 9 stops reduction) the longest exposure that could be achieved was 30 secs. This was not enough to show the effect, so this image was created from 10 successive 30 sec exposures which were then merged in Photoshop using the image stack mode. The unavoidable 3-5 second gap between shots gives a jerky look to the image. It doesn’t work for me.

12 Apostles Sea Stacks - streaky cloud look by sequential shots

Sunset attempt. The sun had just set. With the ND400 filter I found I needed a 4min exposure to blur the clouds well (f22, ISO50, ND400, 24mm); below this and they were still apparent as clouds. This time will vary with the relative speed of the cloud motion which will depend on wind speed, focal length and distance of the cloud from the camera. This works well for me.

12 Apostle sea stacks - 4 min exposure

My goal in the next image was to have the clouds appear to originate from a point in the image which supports the composition. The wind was a westerly and when looking along the beach towards the sunset and the distant cliff top this direction lined up with the natural ‘centre’ of this composition. The sun had well and truly set and the ND400 filter was not needed. Again a 4 min exposure (f8, ISO200, 17mm). Note that the clouds close to the ‘origin’ at the bottom of the image haven’t had as much apparent movement as those further away; this is exaggerated by the wide angle lens (17mm). I really like this image, if only I could get the colour effects as the previous image.

12Apostles sea stacks 4 min exposure

So, a new skill for my artistic repertoire and not difficult technically, but you need to think about a few things:
– which way are the clouds moving and how will this support the composition
– exposing for the clouds and looking into the sunset will put almost everything else in the image in silhouette so you may need to take some higher exposure shots to allow the detail to be filled in later
– a stable tripod is critical
– the light changes extremely quickly at this time of the day, learn how many stops your ND filter is and take shorter exposures without it on to gauge the exposure time.
– even at low ISO there is noise at 4 mins. Next time I will try the noise reduction mode of the camera
BTW if you are wondering how much salt mist is in the air and whether it is encrusting the front of your lens during the 4 min exposure, just turn your torch on in the dark. If you can’t see more than a few metres in front of you then start to worry. I did. Wipe you lens regularly!