Learn about the tools available for pulling focus with various camera setups.
- Even if the cinematographer has a thorough understanding of the underlying physics of focus and optics, and an understanding of human nature, that can be nullified by not having the equipment required to execute the director's and the cinematographer's ideas with the lens. Let's understand why we need focus equipment and standard focus procedures. Now, we talked earlier about how you really can't see critical focus on a monitor. But we can see relative focus, and I don't want us to get the idea that we don't ever use eyeball focus, 'cause we do.
Now, it's a whole lot easier, however, with an aid like a Siemens chart. So Tito, our first camera assistant, is going to roll through focus so you can see this little kind of vibration that you see in the center there. As it gets smaller and smaller you can see that that's critical focus. Little wider and you can tell that that's a little bit soft. Now, you probably won't see the focus change on her eyes, but you will see it on the Siemens chart, okay? That gives us a mark for eyeball focus.
Now, we're doing this using a standard focus rig. We've got a knob here that's connected to a set of gears, and the gears are connected to the lens so that when we turn this knob it turns the ring, focus ring on the lens. Now, the great thing here is that we can mark this white ring here rather than marking the lens. We also have a crank that lets us do both fine control as well as gross, kind of extreme changes in focus.
We can also use a focus whip. The great thing about a whip is that it lets you get a little bit further away from the lens, and that kind of parallax distance between you and the camera gives you a better shot at seeing the distance between camera and the subject. Now, (mechanism clicks) we talked earlier about how you can't determine focus with a monitor; you can't roll through that precisely during the shot on a monitor.
And the reason for that is, during the shot we need to be at a mark on the lens at the same time as the actor arrives at that mark on the floor. Now, they may be behind it slightly, they may be in front of it slightly; however that happens, we can now look at a depth of field chart, and we can say, "All right, were they still in the zone of focus "or were they outside of the zone of focus?" If you're looking at a monitor, you really can't tell where you were on the knob as well as where you were, where the actor was on the floor.
You can't do standard focus procedure with a monitor. So, the way you actually physically do it is that you walk through your rehearsal. So Ashley? We're going to find a first position for Ashley. And that would be behind the ladder over here. And Tito will lay down a focus mark. And then we're going to ask Ashley to do what we call a banana, which is a curved path, which will take her to the chair here.
And that's where Tito will roll focus forward. Now, then Tito will take a tape measure and he'll measure (tape measure zips) the distance to Ashley's eyes. We'll make sure that that confirms what we did with eyeball focus. And also that's where we're going to start out with focus, on the book. Okay, so Tito will go ahead and do our marks on the lens.
Ashley, can I get you at one, please? Now, we'll run through a rehearsal, we'll see if we need to make adjustments to the marks, and that's that; it's clean, it's simple, it's repeatable. That's what we want from every aspect of camera, grip, and lighting: precise execution, repeatability, and confidence and our procedures so that we can do the same thing over and over again and come up with the same results every time: a shot that really works.
Okay, so here we go. Ready, Ashley? And, action. Great.
Focus equipment can be complex and completely separate from the camera. Bill talks about how to use this equipment effectively. In addition, unlike still photography, your camera and the subject in front of your camera may be in motion. Discover how to manage this dynamic aspect of filmmaking, including how to avoid common focusing errors with actors. Finally, get tips for handling common problems with lighting and focus.
- Using the light meter
- Optics concepts
- Pulling focus
- Focus splits and zones of focus
- Composition and movement
- Avoiding common focusing errors with actors
- Solving common lighting and focus problems