The above photo represents a depth of field challenge. This shot was taken this past January on a safari in Tanzania with my Nikon D300 and a Nikon 200-400mm f/4 VR lens. Our guide got us as close as he could without disturbing the animals, but I still needed the telephoto lens to get closer. My hopes of getting all, or at least most of the lions in focus were dashed when I realized how shallow the plane of focus is on a telephoto lens like the 200-400mm.
The first thing that came to mind was to stop down to f/11, f/16, or even f/22 in order to increase my depth of field and get the lions in focus. That causes the shutter speed to slow significantly, however. A general rule of thumb for big telephoto lenses is that you want to shoot at a shutter speed at least twice that of the focal length you’re using. This helps to avoid motion blur caused by vibrations in the lens. The shot above was taken at 280mm, so that means I should’ve been shooting at least 1/560 sec. But f/14 yielded a shutter speed of 1/125 sec which is dangerously slow for a big lens, especially since I was only resting the lens on a bean bag on the roof of our Land Cruiser. I suppose I could’ve increased my ISO to get a faster shutter speed and still have a small aperture, but I’m a snob. I want the best quality I can get out of my camera and I resist raising ISO unless I absolutely have to.
The truth is, there was no way to get all the lions in focus even at f/22. This was one of the biggest lessons I learned about photography while in Africa. Although I wish I could’ve captured all these lions together in focus, the next time I’m fortunate to come upon a scene like this I’ll look for creative ways to work with the shallow depth of field of my telephoto lens. I’m sure you’ll agree that getting closer to my subject was not a really an option in this case!