This is my 3rd T/S canon lens, starting with a 24TSE on the 20D, followed by the 90TSE, and now the 17 on a 5DIII.
This is my Favorite by far. I sold the 24 because on the crop sensor it gave me awesome panos and LOTs of MP addition. When i moved to the 1DsII, suddenly the shift was not nearly as noticeably, and gave me larger rectangles, than wide panos.
I decided to sell the 24TSE and invested in the 17 instead and that was an excellent choice. Other than the lack of a filter, this is by Far the better lens. On the 24TSEV1 I had, switching between orthogonal and linear t/s was a PAIN. This one is never more than a level and a turn away, and it can be stopped at 45* increments!
Images are so sharp, the 10X live view looks almost as good as the no-zoom live view. The FOV on this lens makes everything look incredible, and the focus range is amazing!
Add to this that it takes the 1.4X and 2X very well and you have a Great lens which can easily double as 2 or 3 lenses depending n how much you want to bring into the field with you. Its a heavy lens, but its Built like a tank. The rotating cap location is a bit annoying since you have to reinstall it every time you move since the elements are so exposed but its not to problematic. For those that dont know why it costs so much, look at those front 3-4 elements. Those dont polish themselves and that curve must be insane to build. Working for a lens company I can tell you, the only reason it isnt 2-3X as expensive is because they can make thousands of these lenses.
It is not for the undaughting, however, youll need to understand the t/s principals to make this lens shine.
If you think youll enjoy some Scheimpflug, pick up this lens!