Behind the shot: Caiman Under Stars

Our Caiman Under Stars set of photos was shot over the course of three nights last summer. We were in the Pantanal – a massive wetland region of Brazil, over 10 times the size of the Florida Everglades.

Usually we aren’t content with just taking photos during the day so we often go out in search of nocturnal wildlife. On one of our night walks we came across a swampy area where caimans were lying in a channel waiting for fish to swim past. It was a very dark night with no moon but plenty of stars overhead. I’m not sure where the inspiration came from but we decided to try and photograph a caiman with star trails in the sky above.

It would have been easy to get the shot by first photographing the caiman and then compositing a second shot of the stars. However, we wanted to achieve the effect in a single exposure (so that it would be eligible for competitions amongst other things).

Composing the shot by the light of a headtorch was the first challenge. We were using a 16mm lens on a full-frame Canon 1Ds Mk III so the second challenge was getting close enough to the caiman!

We knew from experience that we could get a suitable star trail image using a shutter speed of 40 minutes, aperture of f/4.5 and ISO of 200. Based on these settings, we manually controlled the output of an off-camera speedlite flash to correctly expose the caiman in the foreground. This produced a single flash at the start of the exposure which froze the caiman’s initial position on the sensor. For the remainder of the exposure the caiman could thrash around chasing fish as much as it liked without ghosting the image (of course this only worked because the foreground was completely dark – if there had been a moon or stray torch beams then there would have been ghosting).

One last detail – at f/4.5 it would have been impossible to have both the stars and the foreground in focus. To get over this we first focused on the head of the caiman, started the exposure, triggered the flash and then shifted the focus to infinity as quickly as possible!

Once we set the camera off we had to wait for 40 minutes with our flash-lights dimmed, swatting mosquitos and keeping an eye out for jaguars before we could move on to the next shot. We would take around 4 or 5 shots before midnight then flop into our beds with our alarms set for pre-sunrise so that we could enjoy the good morning light. Needless to say, we left the Pantanal exhausted!