The Scheimpflug Rule & Focusing 1/3rd of the way

The Scheimpful rule is a type of movement that helps get more of an image in focus. Simply, it's when you move the lens plane to be no longer parallel with the film plane. Remember that the front standard changes focus and the rear standard changes perspective.

In the words of Trenholm.org ; "..state that three fundamental planes must converge along a common line. For the Scheimpflug Rule, the three planes are the film plane. the lens plane and the plane of sharp focus. The plane of sharp focus is the plane on which the camera is focused. In order for the camera to be in focus, these three planes must converge along a single line: the Scheimpflug Line."

So, normally when your camera has the film plane and the lens plane parallel your plane of focus will be as follows;

However, when you apply the The Scheimpflug Rule by tilting the lens plane, you can get more of the foreground subjects in focus. Say there's a dog in front of my tree and I want them both in focus, the diagram would look like so;

The point in which all the planes converge is the The Scheimpflug Line.

To use this rule, you have to focus on your subject first, here it would be the tree using the first diagram. Then you'd tilt the lens plane until your foreground was in focus and it would turn into this diagram above.

Now, any point on the focal plane line will be in focus. The areas around it may not be, but that depends on the aperture you use.

each of the blue and green cones represent you stopping your camera down and closing your aperture, allowing more to be in focus. You will need to stop down to achieve your desired depth of field or you will only have what's on the line in focus.

You can't use this affect all the time, however when you can it allows you to have a quicker exposure than if you were to simply stop down a lot until everything was in focus, as you don't need to stop down quite so much, allowing for the exposure time to be minimised.

Thomas Struth

Thomas Struth has been known to use this affect to his advantage. When shooting people, you clearly don't want a slow shutter speed or they lose a lot of definition, however he wanted his subject (people) in focus alongside the screen behind them. So he used a reasonably shallow depth of field, which meant he could shoot faster. His images didn't result in appearing blurry, despite parts not being in focus. It looks in focus, but it actually isn't.

Focusing in a 3rd of the way

This is a technique to allow you to get more of your foreground in focus.

Take the image below. If you focus directly on the tree, that and what's behind it will be in focus, how much of that will be in focus depends on your aperture. But what's in focus will be behind the blue line. If you focus a 3rd of the way closer, you move your focal plane and allow for more of the foreground to be in focus. The tree, your subject, will still be sharp if you stop down to a small aperture as it will be behind the focal plane.