Recently I’ve been photographing one of the most spectacular sights I know of in nature, hobbies diving low and fast across a lake to catch dragonflies in mid-air. So I thought I’d write a bit about what an incredible sight it is, why getting a decent photo of it is so tricky, and how I went about the challenge.
Incidentally, the best introduction to this would be to watch the wonderful video footage in this short clip from BBC Springwatch, filmed by Simon King in Dorset. It’s the film that inspired me to want to try photographing hobbies so I’m delighted it’s still available: http://www.bbc.co.uk/programmes/p0085bwq
Hobbies are small falcons, they look just like peregrines but are closer to the size of kestrels. They live in Africa during the winter months and migrate to Europe in May, staying with us until late September. They are astonishingly fast and agile, and can catch smaller birds like swallows and swifts. I have to admit that even though I know it’s true, I still find it hard to believe that anything can catch a swift!
Hobbies are rarely witnessed chasing and catching other birds and it’s not really something you could set out to photograph. But in May and June when the adults arrive here, they are often seen catching dragonflies, and in September the newly fledged juveniles are out doing the same. They need to catch a lot of dragonflies to build up their strength for the long flight to Africa. A lot of this hunting (referred to as hawking) happens quite high up, but when conditions are right and there are large numbers of dragonflies emerging from the long grass and drifting over a lake, hobbies will dive down low to catch them. And that’s when things get spectacular.
To stand on the edge of a lake as a hobby drops out of the sky, gains enormous speed, levels out just above the surface of the water heading straight towards you, makes a sudden jink and then pulls up just above your head with a pair of dragonflies in it’s talons, is one of the most awesome wildlife experiences I’ve had!
It’s hard to describe how fast this all happens. I have no idea what speed the hobby is flying at but it’s incredibly fast, on a different scale to the speeds we’re used to seeing birds doing. Initially the hobby doesn’t have a specific target, it’s just building speed and waiting until a dragonfly appears roughly in it’s flightpath. Then it has to adjust it’s course in an instant and with perfect accuracy if it’s to intercept the dragonfly (or quite often a pair of mating dragonflies), and it has to bring it’s talons forward to make the catch. When you see this happen it’s as if there’s just a small flicker in the flight pattern because it all happens in the blink of an eye.
|Dragonflies have great peripheral vision and very quick reactions, and they do try to dodge out of the way of hobbies.|
So how do you go about photographing this? It’s not a great challenge as far as creativity is concerned. You’re really just trying to capture the action as it plays out in front of you. But as a purely technical challenge it’s an extreme one. I think it’s the most difficult action photography I’ve ever done. If you think of motorsport photography as being technically demanding, I can assure you as someone who regularly shoots MotoGP (the motorcycle racing version of Formula One), it’s nothing compared to hobbies catching dragonflies.
The first problem (apart from the obvious point that, unlike MotoGP bikes, birds can appear at any moment and going in any direction) is that hobbies and dragonflies are not very big, so you need to use a long telephoto lens. If you can imagine trying to follow a tight turning fighter jet with a really powerful telescope then you’ll get the idea. Half the time when you aim the lens at the hobby and then look through the viewfinder, all you see is sky or trees because the bird has already manoeuvred onto a different path. And by the time you’ve aimed again it’s often too late, the bird is too close.
|Shooting with a shorter lens is easier but you end up having to crop the image a lot. (This was at 300mm).|
|Using a big lens means you can’t always keep them in the frame. (500mm lens on Canon 7dmk2, 1.6x crop factor)|
Another problem with big lenses is that they’re heavy, and swinging them around for any length of time soon has your arms shaking and your back aching. A monopod or a tripod with a gimbal head are ways to relieve this but then you lose a little freedom of movement.
But the biggest problem with long telephoto lenses is that they give an exceptionally small depth of field. In other words, to get your subject sharp you have to have the lens focused at exactly the right distance. If a hobby is 20 metres away then 19.5 or 20.5 metres is not good enough, the bird will not appear sharp. No human could keep a rapidly moving object accurately focused by continually twisting the focus ring on the lens barrel by the perfect amount. Remember, you have no idea where the hobby will encounter and attack a dragonfly, so you have to be able to track it constantly and keep it in focus. And that means you have to rely on autofocus.
(If you watched the video clip and are wondering how Simon King did it, well so am I! All I can suggest is that video cameras have smaller sensors than digital SLRs which gives the effect of increasing the magnification of the lens but also increasing the depth of field. So he could film the hobbies when they were much further away on the far side of the lake and therefore perhaps slightly easier to track and to keep in focus. He still did an amazing job to get the footage. I’ve never seen anything else like it, so I’m certainly not suggesting it’s easy!)
|With a big telephoto lens autofocus has to be spot on. Half a metre out is close but counts for nothing.|
Modern camera autofocus systems are true masterpieces of engineering. Sometimes I find their speed and accuracy mindblowing. If you’re used to watching a blurred image slowly morphing on your mobile phone screen into a slightly less blurred image, then what a good camera autofocus system can do has to be seen to be believed. Usually you just tap the autofocus button and the image snaps instantly and silently into perfect focus. And if the subject is moving towards you then you hold down the autofocus button and the camera tracks the subject so that it stays in focus, allowing you to choose your moment to shoot.
And modern cameras don’t just have one autofocus sensor in the middle of the frame, they have loads of them spread over a wide area. My camera has 65 (referred to as AF points) arranged in the pattern shown below. This is useful if you want to frame a subject off-centre, as you can nominate any single AF point to track the subject with. It also means that once the camera has locked on to the subject with one AF point, if the subject then darts around and you can’t keep it on that point, the camera can pass the subject on to whichever adjacent AF point finds a subject at roughly the same distance, thereby tracking the subject as it moves around the frame.
|Screenshot from original RAW file showing autofocus points.|
To get the best out of such a sophisticated system you need to understand how it works and set it up correctly to suit the way you’re trying to use it. Many photographers don’t do this and end up complaining that their expensive camera has inconsistent or inaccurate autofocus. I suspect that those using long telephoto lenses tend to make more effort as the results are much worse if they don’t.
Autofocus systems rely on contrast to detect and home in on a subject. So they have an easy time if the subject is a bird against the background of a bright sky. But what if the background is not a uniform, bright area for the bird to stand out against? What if it’s a mosaic of leaves on trees, grassy reeds and ripples on the surface of a lake, on a sunny day? High contrast everywhere. Now it doesn’t matter how many autofocus points you have because they’re all picking up different potential subjects and the camera has no way of knowing which one is your chosen target. Now when you tap the autofocus button a subject comes instantly and silently into perfect focus - but it’s the long grass on the far side of the lake, not the hobby!
|Here the ripples on the lake have proved too enticing for the autofocus system.|
And on top of focusing, there’s another problem. You don’t know when the hobby will encounter a dragonfly and strike but you need to capture the exact moment it does so. So you have to fire off a rapid burst of images, at the fastest rate your camera can manage, at the slightest hint of a flinch from the hobby. With the camera firing at full speed and the viewfinder blacking out as the internal mirror flips up for each exposure, the effect is similar to the stunted animation of someone seen dancing under strobe lighting. Hardly what you want if you’re trying to smoothly track a fast moving falcon!
So how did I go about trying to solve the problem? Firstly, I had to have every parameter of the camera set up exactly right. Here are just a few of them;
Exposure settings manually selected as the action could take place against a light or dark background. The fastest possible shutter speed to freeze the movement.
The fastest possible continuous shooting speed.
Lens image stabilising active in one plane to help with a smooth panning motion.
One autofocus point selected.
Maximum autofocus sensitivity in terms of expecting a subject that changes distance rapidly.
And crucially, the longest possible delay before the AF point would attempt to acquire a new subject if the current subject suddenly disappeared from it’s view.
And so on…
Then, once the hobby had made it’s dive and was starting it’s run across the lake I had to get the lens onto it and panning with it, while at the same time twisting the manual focus ring to get the focus as close as I possibly could. As the hobby approached, now travelling very fast, I had to keep the panning motion matched and try to guide the centre autofocus point on to it, while continuing to manually adjust the focus.
Now came the crucial decision point. Only if I had the AF point exactly on the hobby could I risk touching the autofocus button. If I missed just slightly then the camera would instantly lock onto the background and the chance would be lost. You don’t get a second chance once the lens is way out of focus because you can’t even see the hobby, let alone guide the autofocus sensor back onto it. So it’s a game of dare. You have to be brave enough to keep waiting for the bird to get closer so that it presents a big enough target for autofocus (at the risk of missing the shot if the hobby strikes early). But at some point you have to be brave enough to commit to autofocus and risk losing the shot altogether if the autofocus system picks out the background.
Here are two shots I missed by being too scared or just too slow to hit the autofocus button.
And these are examples of misses caused by not being able to keep the AF point exactly on the bird.
Ultimately, the only way to get lucky was to have as many attempts as possible! But I’m delighted with the photos I did manage to get because they’re way better than I imagined possible when I watched that film on Springwatch all those years ago. Below are a few more of my favourites. You can view them all at full screen size, as well as plenty of others that hopefully help to tell the story, by going to the Hobbies gallery on my website: http://www.kevinwoodphoto.co.uk/album/hobbies?p=1
And finally, whether you want to try and take photos or not, I highly recommend getting out and seeing this at first hand. If you love nature then here it is at it’s most finely tuned!
|Can you spot the kingfisher?|