But it is not tilted the same way as the plane of focus.Ī forest with bluebells, shot with a Canon TS-E 17mm f/4L tilted upwards. When the plane of focus gets tilted, the depth of field area will also be tilted. We all have seen such drawings about depth of field. Having the plane of focus exactly parallel to the sensor you know that the depth of field is also parallel to the sensor. Although it is a bit more complex than this, I won’t get into the details on how depth of field works. What if you introduce a larger depth of field?ĭepth of field is an area in front of, and behind the plane of focus that is also in focus. As you have seen, the pieces of paper are in focus, but the top of the books are out of focus. Up until now I have ignored depth of field and regarded the plane of focus as the only thing that is sharp in the picture. But with tilt the top of the book cover is completely out of focus, while the pieces of paper are in focus from front to back. In a normal situation the plane of focus is vertical, just like the sensor orientation. But also the focal length of the tilt-shift lens will determine the amount of tilt. The more you tilt the lens, the more the focus plane will tilt. I won’t try to explain the physics behind this principle, but it is imperative to understand how this principle affects the place where the focus will be. It tells us how much the focus plane will tilt. This effect is called the Scheimpflug Principle. If you could tilt the lens far enough, in theory, the focus plane would even become horizontal. As you can see in the drawing below, the focus plane will tilt in the same direction as the lens. The focus plane will no longer be parallel to the sensor plane. What Happens When the Tilt-Shift Lens Is Tilted?īy tilting the lens something strange happens. I used the Canon TS-E 24mm f/3.5L II for this setup with an aperture of f/3.5 to keep the depth of field at a minimum, but it also applies for every other focal length. Just imagine the plane of focus to be a flat surface that is exactly parallel to the sensor. But no matter how large or small the depth of field is, it is always parallel to the sensor, just like the focus plane itself.įor now, I will ignore the depth of field. A normal situation shows a plane of focus that runs parallel to the sensor plane.īy closing the aperture it is possible to get an area in front and behind the focus plane within an acceptable focus.
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