The Great Barrier Reef ....photography

They say that daylight has a colour temperature of around 5500 K, but out to sea under a blue sky, this isn’t always the case. It’s funny how our habits as photographers change – or should I say, how my habits have changed. When shooting film, I’d usually have an ultraviolet (UV) filter on my lens ‘to take the blue out’.

While invisible to the human eye, ultraviolet radiation generally records as blue on colour film and as haze on all films. It has a similar effect on digital sensors as well, but of course, many of us don’t believe in using filters anymore.

There is an argument that states, why would you want to degrade the quality of your lenses by placing another piece of glass (or, heaven forbid, plastic) in front. If the lens designers thought a filter was a good idea, surely they would have included it as part of the design. This argument fails in several places, of course, but even so, given digital photography allows us to adjust our image files so easily, many ‘essential’ filters are no longer used. And in any event, the majority of UV filters were sold for ‘protection’ of the front lens element, and you could clean them with a dirty sock if you had to because, if scratched, they were not as expensive to replace as the front lens element.

Not that I ever cleaned my lenses with a dirty sock. Ever.

Here’s the original exposure with the white balance in Capture One Pro 6 set to ‘Shot’ mode. In other words, this is the white balance setting suggested as a starting point by my camera. Of course, capturing raw files means I can change the white balance to any setting I like when converting the file. According to Capture One Pro 6, the Kelvin is 7943 K and the Tint is set to 3.0.

Note, there are no adjustments made to this file at all – it is effectively straight out of the camera. However, you can see quite clearly that it is ‘daylight’ over Australia’s Great Barrier Reef, so what happens if I set the white balance in Capture One Pro 6 to ‘daylight’ (or if I had set the white balance to daylight on my camera)?

At a 5500 K daylight setting, the photo is considerably bluer. And this isn’t what I remember seeing, either. The human eye when coupled to the brain is an incredible imaging device, not only adjusting the ‘exposure’ but also filtering out colours. I remember very clearly how strong and vibrant the colours over the shallow reef were compared to the darker blues of the deep water outside. This colour contrast is lost due to the overpowering blue colour cast.

I’ve taken a dozen helicopter rides over the Great Barrier Reef and every time it is different. In August, I was on Hamilton Island, giving a workshop with David Oliver and Bruce Pottinger. We do this every year and one of the highlights is the helicopter ride over Whitsunday Island and then out to the reef.

On this day, there was a strong southerly wind and the air was very hazy, which means that the images are lacking in contrast. The greater the distance, the more haze you look through and we’re at around 1500 feet (from memory). So, while I didn’t have an ultraviolet filter with me, I could use Capture One Pro 6 to tweak the colour temperature (just a little warmer) and increase the contrast. I also added an adjustment layer to darken down the sky at the top.