Letang Is The Truth wrote:what is difference between XD and IMAX?
XD is Cinemark
's branding for their specially equiped theaters with higher end Barco brand projectors and higher quality speaker systems. I don't know if the projectors get larger "upscaled" film prints or if they are just using more advanced processors and are feeding them the same digital video that other projectors in the building get. I assume they're all digital projection, in which case it would probably be the latter. I doubt they get distributors to create a special transfer just for them.
Imax originally was a new size of film/camera system on the production side and a high end projector with extremely large screen/laser aligned sound system. Movie's have typically been filmed on 35mm film, with some larger budget things/action scenes being filmed on 70mm. Imax film is even larger than that. The larger the film, the higher the resolution (think of it like going from 720p to 1080p, sort of)
When movies, such as Apollo 13, we released in Imax (as opposed to Faux Imax, which comes later), they had to contend with several limitations. It was not filmed with Imax cameras, and did not fit properly onto Imax film. So it was cropped to approximately 16x9 and had some scenes cut out due to reel length limitations. This is also why you will notice in movies like Tron Legacy and The Dark Knight that it jumps between 1.85:1 (which basically fills your entire HDTV) to 2.35:1 (which leaves black bars on the top and bottom of the screen).
Over the past several years when Imax releases have become a growing trend, theater chains have began taking the largest auditorium in the multiplex and upgrading it to an Imax projector system. This isn't quite the same thing - many times the screen size is much too small or the wrong shape all together. Also, Imax has been getting into the digital projection business, which most technical people call Faux Imax.
Film has a much much higher resolution than anything digital can currently do. So if something was shot on film and is now being shown in a digital Imax theater, it is "downscaling" the quality. Conversely, something not filmed with Imax cameras but transferred to Imax is "upscaling" it, which is the same principle as watching a standard definition DVD in an upscaling player.
That's why The Dark Knight Rises having so many scenes filmed in Imax is a big deal - it's almost akin to saying that some of the Penguins game is being shown in SD, while other parts of it will be presented in HD. They wanted to film the entire thing in Imax, but the cameras are ridiculously noisey and soft dialogue scenes wouldnt work.