Please comment below on how I could have improved the title of this post. It's an article about pre-focusing your DSLR to capture moments that otherwise couldn't be captured, but I can't think of a clever title. I guess I should just write the article already…
There have been several situations where I walked away from a shoot with a great picture that no other photographers at the event were able to get. The trick I used to get the picture is called pre-focusing, and I think photographers often overlook this helpful technique. This technique is extremely useful for sports or action photographers who want to capture fast-moving moments.
One of the first times I used this technique was shooting a high school Junior Miss Pageant. The girl was about to smash three blocks of ice with her head and two hands at the same time. Especially in the low light, I knew that I probably couldn't wait for the camera to try and autofocus at the very instant that the girl smashed the ice. Autofocus would take too long and I'd miss the shot. So I focused on the blocks of ice, locked the focus by using the switch on the lens to change it to manual, and then waited for the moment and snapped the shot. Since I didn't have to wait for focus, I walked away with a cool shot, and the other photographer (with a $6,000 lens on) walked away with a blurry mess that was barely recognizable as a photo.
Another time I used this technique was while watching a dolphin show. The trainer climbed to the bow of a boat and held out a stick. I didn't take a genius to know that the dolphin was about to leap out of the water and touch the stick with its nose. All the other photographers waited and waited for the dolphin to come out of the water, then tried to autofocus and grab the shot at the right instant. It didn't work for most of them. I focused on the stick, locked focus, and then simply waited for the dolphin to squish my shutter button. Yahtzee!
Another great situation where pre-focus is helpful is when shooting the classic water drop falling into a beautiful blue bowl of water. Since the lens is so close to the subject, and a low aperture value is used to get a fast shutter speed, there is usually a shallow depth-of-field in this type of shot. Because of the short depth-of-field, it can be tough to capture proper focus at the very instant the drop hits the water. The answer? Obviously, it's pre-focusing. Take this shot by putting the camera on a tripod, place a pen or your finger on the surface of the water where the drop will hit the water, focus on the pen or your finger, lock focus, then just wait for the moment and don't worry about not focusing fast enough.
An alternative to using the traditional pre-focus technique is to use back button focusing. This will allow the photographer to separate the focus from the actual taking of the picture which will help dramatically in getting action photos.