This was neatly done.

Stitched image of the NIF Target chamber.

Target chamber (big blue sphere) is ~36ft in diameter and extends thru three floors of the building it is contained in.

That's a really cool picture. In terms of stitching, though, it's really, really easy, because of all the reference points. Try stitching sky. :-p

Depends on how the photo was taken.

If it was taken from a camera carefully mounted on a special tripod where the rotational center was at the camera's focal plane, then yes, stitching is a doddle.

But if it's from handheld photos (and the photographer isn't careful to rotate around the camera's focal plane), a set of complex 3D objects like that makes you run into the issue of the parralax changing, making various bits overlap differently from tile to tile. It's worse, even, than the situation where you do large outdoor panoramas and someone is walking across from tile to tile.

In fact, looking at the photo more closely, I see some blurry bits that look like just that situation happening.

You can work around this by exporting your auto-tiled image as a Photoshop file, and painstakingly editing the layer masks so that the misaligned objects don't appear doubled or blurred. I rarely have the patience to do that.

In fact, the more I look at it, the more it seems like someone took the photos on three separate floors, and fudged the stitching carefully to make it appear as though all the photos were taken from the same spot.

Yeah. It is several photos glued together with very odd stitching. The middle section don't match up with the top and bottom sections at all.

Exactly the point. The Photographer had to setup on three different floors. Each floor has a hole in it, and the floor goes all the way around.

The stitching isn't a simple match of overlapping rectangles.

Actually Tony, if you tilt the camera at the focal plane your images aren't likely to line up very well. You need to rotate about the entrance pupil of the lens. A lot of sites mistakenly call this point the "nodal point" (as I used to).

They may have used a tilt/shift lens to correct for perspective, making it a lot easier to stitch together three images taken at different heights. Or it could have been corrected in software.

That's what I meant, but used the wrong word to describe it. What's the correct term for the spot on the camera where rotation results in no change in POV center?

With regards to the name of the point, I don't know if there is a proper name for it. It's the center of the entrance pupil though. Even the page I just linked doesn't give it a proper name and has a note about ignoring or not getting hung up on terminology as long as you're finding the right point.

The Metadata on the image says it was saved with Photoshop CS3, shot with a Canon 1Ds @17mm, 1/10@f5.6 by Jacqueline McBride.

It's funny, but all the text I can find accompanying the photo on the net keeps talking about the significance of the subject matter rather than the creative/technical process that went into taking the picture.

Well, if it's a spot, it wouldn't contain the word "plane"