A while ago I had rented the Canon TS-E 90mm f/2.8 lens. Why? I wanted something fun to play with, and had always been curious about the TS/E lenses. The 90mm also had a reputation for being very sharp (which it was!) and it had a high maximum magnification as well.
The tilting mechanism was what I was most interested in, and was also the weirdest thing about the lens. The plane of focus does *not* stay parallel to the lens as you tilt it. It also moves as you focus the lens in addition to as you tilt it. It’s still usable hand-held but when it’s absolutely critical you nail the plane of focus, a tripod is in your future. A good explanation of how tilt works can be found here from Northlight Images.
When you abuse the tilt, you can blur the heck out of an image like so:
More careful use though results in a depth of field as deep as your heart desires. I don’t have any great examples of it, but this will do. I didn’t nail the entirety of the front sign, but the bottom of it is in focus as is the far sign:
Assuming you can focus well and hold it steady, the lens is also sharp and I love the colors and ‘pop’ I got out of it with so little effort:
Ultimately though, I wouldn’t buy the lens for myself. I already have a very excellent f/2.8 lens of about that focal length in the form of the 100mm f/2.8 USM Macro, and I think the tilting and shifting would be much more useful for me in a wider focal length.