From 2003 until around mid 2007 I used various zork shift adapters with various Canon bodies, 1ds MKI, MKII, MKIII, 5D nd 5D MKIII. I used the adapters for Pentax 67 glass, Pentax 645 glass and Mamiya 645 glass. I found for my landscape work, that the shift adapter for the Pentax 645 worked the best. I used the Pentax 35mm FA F3.5, 45mm, and older MF 150mm. By far the best lens was the Pentax 645 35mm FA. The Pentax 67 glass to me was much heavier, and just didn't hold up in the corners on shifts. The Mamiya 35mm glass was more abundant and cheaper but again seemed to fall off in the corners. I used the older Mamiya 35mm, and 55mm.
Also Canon has released much better wide angle TS-E lenses. When I was using the Zork, the Canon 24mm TS-E was not a very good lens on shifts. The newer version, excellent even all the way to 12mm (on a 5d MKII). Plus you can get tilt and shift in the same plane.
You can shift up to 18mm left and right. With the camera in portrait orientation you can get a 3:2 landscape image with 3 stitches.
Easy to rotate around the lens
Quick release allowed for very quick shifting
Well made, good mounting both to Pentax and Canon, I never had any problems with my adapters and they were used hard.
No parallax issues since with the tripod mount on the adapter you could setup the rig to shift the camera not the lens. Images lined up perfectly
Not much light fall off since you were working with the larger image circles of the Medium format glass on a 35mm lens.
Not easy to adapt to a Landscape orientation to allow shifting (I did it with modified L bracket) The newer models may have this issue fixed. I had
several conversations with the U.S. rep about this.
Hard black vignetting at edge of shifts, i.e. on a full left shift of 18mm, you would get a hard black edge on the image about 1" wide from hitting the edge
of the cameras image box. This was a straight line not just the corners as normal vignetting. The only problem with this was that when you
attempted to stitch, many software solutions at the time would try and blend in the black which ruined the image. If you cropped it out, the software
would not work since the images all did not have the same size. This also may be fixed in newer solutions. I tended to just load all three images
into photoshop and manually blend them.
Overall I used the Zork shift adapter to create a larger resolution file not panos. It gave me around a 27mp image with my 1ds MKI and then later on a
about a 40 to 42mp image from the ads MKIII. I briefly used the setup with a 5d MKII but found the resolution of the 5D MKII just a bit more taxing on the shifts. For some reason I also found the manual focusing harder with the 5D MKII viewfinder. Note, I did not use live view and should have as it would have made the entire process much easier. I was a slow convert to live view.
It's a great tool, but as DSLRs pick up more and more resolution the needs to shift for size have dropped. Also the max shift of 18mm really won't give you a "true" pano so for pano's I went back to nodal point and pano head.
As far as images, I agree there are many out there, however depending on usage, it would be hard to tell much i.e. most of my images aren't panos but instead normal 3:2 ratio images, just much higher resolution.
For me the ability to shift with the camera off level was a very big advantage. I took thousands of images with the zork/canon combination in both portrait mode and landscape mode (3) shift each and the results were always excellent.