Wasn't sure where to put this question, so I figured the general forum was a safe bet. First, feel free to do some myth busting here. I've done a lot of research, but am not certain the conclusions I've come to are correct. I want to start getting into pano's, and more specifically, vr tour type shots, as they are all the rage for commercial purposes, and would be a great selling point for many of the businesses here on south beach, not to mention with realtors. All the research I've done on vt rigs suggest that the proper way to do these panos is to center the lens' diaphragm to the pivot point on the tripod. I have a great kirk bracket that will allow me to achieve that center point and an L bracket on my D2x, so mounting is not an issue. The problem I have with that is, how does one determine that? I've seen lots of info on the fact that you need to do that, but none at all on how to figure it out. I suppose on shorter focal length lenses, I can figure it out by visible inspection. I have a shoot coming up where the end result is going to be a VERY large banner as a backdrop for another shoot (I know... I'm not sure I understand it either ). The shoot centers around a specific hotel here on ocean drive, and I wanted to try a very high res stitch of several shots done with my tilt pan head to get better resolution. I was planning on using either my 85 f/1.4 or 135 f/2 DC for that attempt. That's where things get a little harder to figure out where the exact diaphragm plane is on the lens. I would assume on say, the 70-200 that the tripod collar is put at that point, but again, can't be sure of that (would certainly make the most sense from an engineering standpoint) So... any of you math wizards out there know of a formula based on focal length where that point is? IF nikon did diagrams on their lenses like others do (sigma for example) I could at least get close by eye, but I don't see any such resource for nikkor lenses. Any help would be appreciated.