IMAX update
There are now three IMAX formats:
a) 70MM film IMAX, which has an 18K horizontal resolution, and expands the height of the picture as displayed above.
b) Digital IMAX (aka LIEmax), which has a 2K horizontal resolution (similar to a 1080p television), and which expands the picture height somewhat, but not to the full height of 70MM film.
c) IMAX with Laser, which has a 4K horizontal resolution, and which expands the picture to the same height that 70MM film does.
IMAX hopes that IMAX with Laser will quell all the LIEmax criticism that they suffer with Digital IMAX. Whether they will succeed remains to be seen. 4K resolution is a poor substitute for 18K.
Anyway, now for the bad news.
Star Wars VII for 70MM IMAX is going to be
2D only. And most of the theaters that are capable of playing 70MM film IMAX, are choosing to instead play it in LIEmax so they can have 3D.
http://screencrush.com/star-wars-the-force-awakens-imax-theaters/
So far only a handful of theaters around the world have IMAX with Laser installed, so most people will not have that option (maybe next Star Wars).
Here is an official list of the handful of theaters that are going to play Star Wars VII using either 70MM film or IMAX with Laser:
http://www.imax.com/community/blog/star-wars-the-force-awakens-imax-tickets-on-sale-now/
The rest of us are going to be stuck with LIEmax.