Some of these were some experimentation with tilt-shift (the first three.) Tilt-shift is where you actually remove the lens and tilt it a certain direction to bend the light entering the aperture. What this actually does is bend the focal plane. In a normal camera, the focal plane is completely perpendicular to your camera. However, as you can see in the photos, tilting the lens makes the focal plane bend in that same direction. The focal plane always stays perpendicular to the lens, thus when the lens is tilted from the camera, so is the focal field.
You can buy accessories that do this for you, and that is a much safer way of doing it, but it takes a heck of a lot of the fun out of it.
