The Limits of Autofocus

I spent much of the last few weeks in the company of wild maleos, an endangered bird species on the island of Sulawesi. It was hot, hard work, but I felt privileged to spend time in the company of a fascinating, lively, and slightly weird bird. As I mentioned a few days ago, maleos gather near the coast to lay their single, enormous egg in the hot sand, there to be incubated by the heat of the sun.

They spend most of their time digging,  which allowed me many opportunities to capture that behavior (see below) but there was more going on as well. For birds that share a communal nesting area, these guys don’t seem to get along very well!  When they weren’t digging their own nests, the males of each maleo couple spent a lot of time chasing away other birds that had the temerity to try and nest too close. This process put the birds in some pretty striking poses, like this male huffing himself up to look big, and scary, to another bird that had strayed into “his” area.

Working with a 600mm (equivalent) lens in a tiny blind, I managed to get some good close-ups, but was constantly plagued by the shallow depth-of-field at that focal length. Essentially, I had to lock onto the face (since even if nothing else is sharp, the eyes must be) with my auto-focus and try and stick with it, as the birds ran circles around me and one another. In the end, I lost more pictures than I got – including some spectacular aerial fights that I just couldn’t lock onto. But I still managed to come away with some nice behavioral coverage.

Autofocus has been an enormous boon to wildlife photography, as any of you who remember manual focus will testify.  Many of the crisp action photos we see today would have been virtually impossible when I first got started – you felt lucky to get one picture of a moving animal on a roll of film in focus. Now, with focus tracking, you can get entire sequences of birds in flight, or animals on the run.

But even the best autofocus can’t work miracles. I have yet to use a camera that works as fast, and as flawlessly, as the human eye: maybe I’ll live long enough to see that…  In the meantime, for this shot of a charging maleo I had to lock on to the eye of a moving bird coming right towards me, his head slightly off-center.  I got it, but I missed a dozen others as my autofocus struggled. Believe me, there is nothing so maddening to a photographer in the middle of the action as an autofocus that is searching in and out for something – preferably a hard edge – to lock onto. At moments like that, a fraction of a second can seem an agonizing eternity.

My autofocus clearly did not like the bird’s black feathers, and the various predictive tracking modes didn’t work well in this situation. So I was left with placing my focus point manually – a high-risk enterprise with a moving animal. In the end, I got some shots I’m happy with, but I keep thinking of those I left behind…

Nikon D300 with Nikkor 200-400 lens