1. Pulling at the wrong speed
A rack focus done right will be seamless and unnoticeable by the audience. Done wrong, however, and it can attract a lot of unwanted attention. Part of mastering the rack focus is to understand the mood, the pace, and the tone of the scene. It will also largely be determined by the camera move itself.
For me, I tend to pull too slowly on a lot of camera moves. I use rehearsals to find the ideal speed before the camera starts rolling. You should be wary of how fast you are pulling focus and if shooting digital and there is playback, watch the monitor to get a sense of your own speed and habits.
If this becomes a problem for you, spend a lot of time practicing between takes or while building the camera in the mornings. It is also essential to remember that lens focal distances are on a logarithmic scale so that the closer the focus is distance-wise, the faster you will have to pull.
2. Making too many marks
I’m sure all of us have been guilty of this at one point where a scene has multiple actors, a few different dolly tracking moments and various pans. These types of shots are few and far between, but a more complicated shot often means a more complicated marking system.
Marking on a lens or on a follow focus disk should be limited as much as possible. Only the essential marks should be kept there. If you’re like me, you probably have a few “back-up” marks in mind each take in case an actor oversteps their landing spot or something else unexpected happens. Don’t mark too many of these.
Having too many lines on the lens or follow focus will only turn it into a puzzle that needs to be figured out in the middle of take. You already have enough to worry about in a scene, why make it more complicated? If you do find yourself adding tons of marks, at least number them in the order you need to hit them so you can quickly determine which is which.
3. Not paying attention to rehearsals
Rehearsals are rare these days, especially in the digital realms. Don’t let them go to waste. Even if the rehearsal is only a blocking rehearsal without cameras, you should watch intently. Learn how the actors are going to be moving about the scene. Learn what line they say right before they get up. You may not know where the camera will be yet, but you will at least have an idea of how the scene will play out.
With camera rehearsals, pay attention to the timing on your rack focuses (see #1), the timing of the dolly moves, and also be aware of what the talent is doing in the scene. If they’re on the top of their games, actors will keep solid continuity and there may be certain lines they lean forward on — being able to predict these moves is important.
4. Focusing on the wrong part of the scene
This is a literal statement. Make sure you know which part of the scene you are to be focusing on. By default this will be the lead actor or the strongest character within that scene. If you’re shooting close-ups, this is a no-brainer.
But shooting a large master or a medium close-up can present many possibilities for focus. Do you focus on one actor, then rack to the other? Do you split the focus? Does the actor walk into focus or do you follow him?
Having a rapport with a certain cinematographer will answer many of these questions before you have to ask, but if you are ever unsure, it is best to speak up. A quick, “should I follow him when he leaves?” is often all you need. And it’s much better to nail the scene the way the director of photography wants you to than to have had a misunderstanding about the focal points.
5. Focusing too close
This issue was first brought to my attention by David Elkins’ Camera Assistant’s Manual (an essential read, grab a copy if you haven’t already):
If the operator tells you that the focus is soft on a close-up shot, you are probably focused too close. Whenever this happens you should carefully shift the focus back slightly.
Having an operator tell you that focus is soft during a take can be stressful, but remember David’s advice. It’s better to try and nail sharp focus than remain soft for an entire take. If you end up focusing the wrong way, the scene was already blown anyway so you can’t do worse!
Keep calm and carry on
Remember that nobody is a perfect camera assistant (though some come close) and that pulling focus is a hard job to do. These are just a few common problems that I have experienced and seen others go through. Don’t be defeated if you found this list describing your own focus pulling problems. As you gain more experience, it becomes easier to scratch these off one by one and learn from them.
Did I miss any glaring mistakes you have made or seen others make?