The journey to high speed bat photography
It was such a sticky October afternoon as the sun went down over the Kimberley. The rocks were still hot to touch and I was covered in bat guano, orange clay and sweat. I wriggled down in a sitting position on the rocks and watched. One by one, bats flew out of the cave as the flash briefly illuminated them. The road to success had taken place over several years but finally, victory was mine. One of my favourite books as a kid was Stephen Dalton’s Caught in Motion, a fantastic book written as a photographic essay on high speed photography of animals. To this day Stephen’s photography is ongoing in this field, and much of his work in the 1980s is still highly regarded, even by modern standards. He worked with a high voltage airgap flash, low ISO transparency film and an old photocell trigger to freeze fast and delicate subjects in flight while retaining incredible depth of field and detail. My journey into high speed wildlife photography began in North Queensland with my first digital SLR in 2006. Every year Buff Breasted Paradise Kingfishers arrive in the region to breed after a long flight from New Guinea. Easy targets, they hollow out termite mounds in which their nests are built. They follow predictable flight paths to and from the nest and become very accustomed to humans, especially along walking tracks. Not only that, but their spectacular red, blue, black and orange colouration is topped off by two long white tail streamers – making them excellent subjects.
Setting up to photograph them was not so hard. I only had one flash, a wide angle lens and an industrial infrared sensor to trigger the camera. That was enough; I set up the camera, pre-focused the lens and aimed the sensor and its reflector across the path of the bird. All I had to do was walk away and come back to check on it once in a while. I took many photographs of these birds this way, sometimes they were taking food back for their babies, other times flying out of the nest.
For a few years I put high speed wildlife photography on the back burner, rarely dusting off the gear. Last year, I decided to get back into it to see what I could do. Bats were something I always wanted to photograph in flight but for some reason I spent years thinking about it and never actually putting it into action. Seeing bats flying predictable paths along forest trails, through road culverts and out of caves really got me planning how to actually do it.
It was at my friend Stuie’s place in Cairns that I decided to take bat photography seriously. In his roof are hundreds of mastiff-bats which emerge every night, tumbling out of the roof and flying off into the darkness. Fast, high flying and alert, they are a massive challenge once they get clear of the roost. We set up the reflector and sensor so that they would trigger the camera as they spread their wings after the initial 2m free fall. I used three flashes to try and get the most light in the shortest burst (more on that later). As the camera (Canon EOS 5DIII) takes 56m/s to respond after being triggered there is a little guesswork to be done. A bat flying at a modest 12km/h will move around 18cm (two body lengths) in three dimensions in that time. Many bat species are much faster. This is more than enough to put it out of the frame or well out of focus. Both of these things happened and we ended up with no sharp images. But it was a start.
Work got in the way for a while, but I had a chance to try again in the Kimberley region of Western Australia soon enough. Many caves contain colonies of dusky leaf nosed bats, a gorgeous slow flying species that shuttles in and out of the caves for the first hour of darkness. Preferring confined spaces made it easy to try my luck. Armed with four flashes made life a bit easier. I set up the single infrared trigger in the flight path of exiting bats. With their habit of darting about unpredictably, it was hard to get them exactly on the focal plane as the shot was being taken. I did take some on the wide-angle lens, but they were small in the frame and had to be cropped significantly. My 100mm lens got nothing of any worth. It was fun setting up and having them fly around my head as they came and went from the cave, often triggering the camera while I lined it up. It was not ideal though, I needed a better way. How would I get true precision? I needed the flashes to fire exactly when the bat crossed the beam. Since it was dark anyway, I decided I had a huge advantage – unlimited shutter time.
Some photographers that have tried their hand at bats are using a system that keeps the camera’s shutter open for a long time, but with a second high speed shutter over the front of the lens to keep it dark until a bat crosses a precise beam on the focal plane and in an instant opens the secondary shutter and fires the flashes. It does work but is expensive to buy or make, and bulky. Having the shutter open all of the time must burn batteries up and use loads of shutter cycles not to mention all that power pumping through the sensor must create some hot pixels. I like the system, but decided to go my own way and save some serious money as I went. The idea was to have two beams that are totally separate from each other, one to fire the camera and the other to fire the flashes. A bat would fly through the first vertical beam, triggering the camera into a 1-2 second exposure. The second beam which was less than a meter away would only fire the flash, and the camera was focused on that one. As the flash responds extremely quickly, this would be no problem. So basically by the time the bat reached the flash, the camera would be ready for it. I made up a simple infrared trigger to be used on the flash, but one problem remained. The fastest bats would not trigger the camera long enough. A fast object breaking the beam would be ignored. I needed a way to make it hold the circuit long enough for the camera. A fast, simple solution I found was a capacitor and a second relay. Now even the fastest bat had no chance! The second problem was that of lighting. The faster the object you are trying to photograph, the shorter the flash duration needs to be to freeze it. Speedlights usually have the same level of light output, but the more light is needed, the longer the flash tube is illuminated. At 1/1 power, even a slower bat or bird will be hopelessly blurred. You have to dial the power right down as low as possible. At 1/64 there will still be some noticeable blur on a moderate to fast bat. To get the required power at a bat-stopping 1/128, more than one flash will be needed; the more the merrier. Expect to be using four or more even for close range work. It was a road culvert near Hall’s Creek, Western Australia that was my chosen test site. There was a sizeable colony of wattled bats (Chalinolobus spp) roosting in abandoned martin nests under the road. I set up beam number 1 about 1m inside the culvert on the floor, aimed at the ceiling where the reflector was taped. At the entrance I placed beam number 2 attached to a master flash. The three other flashes were connected to it by Canon’s optical wireless system. The master was a Canon 580EXII, I had two Yongnuo 600EX-RT units and a single YN 560IV. The bats poured out of the culvert, constantly flying back in to rest, before flying back out to feed. I stayed all night at this site, camped at the entrance with the flash going off like crazy. I seemed to get more bats triggering the setup while flying in rather than out which meant less images. But those that did fly out and trigger both beams were perfectly in focus and exactly where I wanted them in the frame. I could call success at least on that, but another problem reared its ugly head – poor synchronisation. The master flash would fire at a slightly different time to the others, which weren’t perfectly synced either. So I would have a slight ghost image from the 580EX and a bit of blur from the others not quite firing at the exact same moment. There had to be a slightly better way.
It was back in the stone country of the Kimberley that I tried the next experiment, physically wiring the flashes together via the PC SYNC ports. All of the YN 600EX-RT units worked perfectly together but would sulk when any other was added to the group. The Canon 580EXII would fire but suppress the others, while the YN 560IV would not only suppress the others but fire about a dozen times in a fraction of a second. This was not good enough so I had to improvise and quickly make an optical slave unit from a phototransistor for the 580 and 560. Only the three YN 600EX-RT units were connected to the flash trigger directly while I had to trigger the other two units via the improvised slave trigger. It was annoying but after some fiddling around, they all fired in unison with zero blur. It was now time to take this setup to the escarpment.
I cable-tied the flashes to sticks and wired them together and to the flash trigger, placing them either side of my target area, zoomed and aimed perfectly so as not to waste any light at all. With a duration as low as 1/20 000 of a second, all the light from all of the flashes needed to be right on target. The final flash was on the roof aimed down. The first attempt was with my 16-35mm lens. This gave me a good idea of what was flying through and what to expect, though major cropping was required. I missed a single ghost bat that flew too low. The most photographed species was the ubiquitous Dusky Leaf Nose (Hipposideros ater) and a single Orange Leaf Nose (Rhinonicteris aurantia). I needed closer images so the following night I switched to my 100mm f2.8L lens.
It was such a great feeling to watch the bats fly in and out of the cave with the flash going off, checking the photos and seeing the images shown here. Perfect focus, no blur and great composition. Currently I am working on a tutorial on how to build the devices you will need. Very cheap and surprisingly easy!