Originally posted by hoanpham You place your question in the wrong place, but I may have the answer you looking for...
Great suggestions,
hoanpham. I (still)
use this setup with a medium format Zeiss 50mm, and it does the "shift" part of the job admirably. (That Zeiss may be too long for you on APS-C, but it is ungodly sharp!)
NEX is probably your best option, if only for the excellent focus peaking and form factor. Here's why:
Shift lenses correct for perspective distortion (by using the less-sharp edges of a too-large image circle), and if you shoot digital, almost all basic software can do the same thing equally well, even non-destructively during raw processing. Yes, they also allow for expanded field of views when stitching images in post, but just rotating the camera can do that these days. Tilt lenses, in landscape photography (not that "lensbaby" stuff), are used for getting nearly endless depth-of-field (thanks Capt. Scheimpflug!), which no software can do as well as tilting a lens (except focus-stacking, which requires lots of shots, and is a no-go if leaves are blowing, clouds moving, etc.). You probably know all this, of course, so my point is only that Tilt is more important than Shift these days.
However, from my experience, I can tell you that SLR viewfinders, even full-frame ones, are too small to accurately assess the focal plane tilt. So, most pros use live-view, unless they are really seasoned tilters, where they can calculate it based on experience. NEX systems shine here because their focus-peaking is much easier to see than Pentax, and allows you to easily see the tilt of the focal plane while you compose. (Sony also makes some of the best articulated LCD screens out there!) Canon has no focus-peaking in full-frame (unless I've missed it).
So, I'd strongly suggest going with
hoanpham's earlier suggestion of an NEX body, tilt lens adapter, very good wide angle full-frame lens, or shift lens if you must have it. The tilt is where your money is at, the shift can be accomplished in software. Full frame advantages diminish when looking at these requirements.