Tuesday, January 08, 2013

Another Look at 3D

Regardless if you like 3D or not, more and more programs are being produced in 3D to the point where there is saying "if you can't make it good, make it 3D".  I actually like 3D and look forward to day my home cinema is full 3D.  In my opinion, 3D [when done properly] adds way more than it subtracts.  

The big question is, should older films be up-converted to 3D like animation?  Disney/Pixar have pretty much up-converted all their animated films to 3D and most of these are available on Blu-ray Disc 3D.  I don't have a problem with this because the original 2D image was created with a computer, so generating a 2nd eye perspective is relatively easy.  What about live action like the 6 STAR WARS films or I, ROBOT?  In the case of the episode 2 and 3 or STAR WARS series and I, ROBOT, most of those films were shot with the actors in front of a blue screen and virtually all the back ground is CGI, so it can work.  The actors may look a bit flat though.     

Cross Eyed 3D Image
 The image above is was captured using a standard digital camera mounted to a tri-pod.  It is simply a case of capturing an image, then capturing a 2nd eye perspective of the same image.  All I did here was to rotate the trip-pod [off the front leg] anti-clockwise about 10 degrees for the 2nd angle.  I then used Paint in Windows to create the image and add the text.  The alignment was done viewing the image cross-eyed.      

To view this image in 3D, all you need is to be able to go cross eyed and let the magic happen.  For 3D to work, your eyes need to be equal strength and it has been documented that many of the complaints about 3D such as head aches are related to undiagnosed eye conditions.  If you are seeing this correctly, the plant should have a good detail and depth be in focus from top to base and the 3D letters should appear to float in front of the image.  The only real good thing about this type of 3D is that you don't need glasses to view the image.  Therefore, you can store 3D images on a portable device like a smart phone or tablet.  The problem is that you see the original elements to the sides of the 3D image and this can be distracting.   


Analygraph 3D is one of the oldest types.  It uses colour filters to cancel opposing colour accents of the left eye/right eye perspective added to the images.  The result is an image that is seen as 3D but colour fidelity is lost.


DOLBY 3D is a passive system that is used in cinemas.  Unfortunately, many cinemas have changed over to REAL D systems due to the high cost of the DOLBY 3D glasses [being damaged].   The DOLBY system uses colour tinted optics similar to Analygraph and maintains full colour fidelity.  A special filter wheel is installed in the projector and syncs with the full frame left and right eye images.  I still think this system is the best passive system and wish a consumer version was available.  The only way to install this system into a home set up is to use two projectors and use the lenses from one set of glasses to provide the filtering.  Then comes the challenge of the video processing.  Costly and technical and why not too many have done this.   


REAL D which use pollarized glasses.  A shutter device sits in the light path of the projector and a special silver screen is required to keep the light polarized.  The glasses are cheap and it works for a commercial cinema.  A home version is also available.    

Active or shutter glasses are the most common type of 3D for the home.  The glasses use LCD to block the light for each eye at a rate of 120Hz with some of the newer systems offering 144Hz. 

The 144Hz systems tripple flash each eye and produce the smoothest 3D and is what speed the D-Cinema systems operate at.


 AVATAR was one of the first live action films to be shot and projected in 3D.  The Genisis camera was specifically designed for the shooting of this film.  The above image is a side by side 3D image showing left and right views.  The bottom image is what the 2 images look like when viewed without the glasses.

AVATAR was shown in cinemas in both CinemaScope and flat [1.85:1].  When it came out on BD, it was presented as full frame 16:9.  One possible reason James Cameron changed the Aspect Ratio for the home release is that 3D images can look smaller than their 2D equivalent when the 3D effect is made to create a really deep field.  It is possible James Cameron wanted the image is be as big as possible and because most of the world is 16:9, decided to fill those screens.  


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