For TS Lens users. Scheimpflug Explained

dkoyanagi

I found an excellent video on YouTube that explains Scheimpflug on a view camera. This video was a big help to me in trying to figure out how to focus my 24mm tilt-shift lens.

http://www.youtube.com/watch?v=gR4m70xr9mE

Of course the mechanics of a dslr and ts are different from a view camera (small viewfinder and only one axis of tilt/swing), but the principles should be the same.

dkoyanagi

Here are some test shots from my 24mm TS-E. I used three CD cases for this test, two standing vertically and one lying flat. The first is shot with 0 movement. I focused on the "T" in "Richafort" on the black CD cover.




I then began swinging the lens to the right in 1 click increments.












Here are some things I noticed:
1. At click 0 the plane of focus starts parallel to the sensor plane. As I swing the lens to the right the focus plane rotates. By the fourth click the focus plane is parallel to the front of the Mozart CD case, so the entire CD case is in focus.
2. At click 4 the black Richafort case is completely out of focus, even though it is the same distance from the sensor plane as parts of the Mozart CD that is in focus. This means that the focus plane does not intersect that part of the black case so it remains out of focus.
3. The aperture stays constant at f/3.5, so the dof does not change throughout all six exposures. You can tell because the focus on the lettering on the horizontal CD case does not change as the lens is swung to the right.