The Evo 3D comes equipped with dual 5-megapixel cameras to capture stereo images needed to produce a 3D picture. While each camera's sensor is capable of 5mp resolution, in 3D picture-taking mode, the resulting image from each camera is down-sampled to 2mp. A physical switch toggles between 2D and 3D mode for taking pictures or recording a video. In 2D mode, only one of the cameras is used, and for still images, the full 5mp is utilized. 2D and 3D video can be recorded in 720p resolutions. (Sprint originally advertised the Evo 3D as being able to record 1080p, but retracted their statement and later corrected that the 1080p spec applied only to video playback.
The 3D image displayed by the Evo 3D is autostereoscopic; the user will not need polarized glasses to perceive the 3D effect. The exact 3D technology utilized by the Evo 3D's display is still unknown but could likely incorporate either a parallax barrier or a lenticular array.
A parallax barrier is a second LCD layer above the main LCD display that forms a light barrier designed to block certain pixels from a particular eye of the user. For this type of barrier to function properly, the user's face must be placed at a specified distance and angle from the screen. This position where the parallax barrier functions properly is known as the sweet spot. If the user moves his/her face outside of the sweet spot, the parallax barrier unreliably blocks the correct pixels, and the intended stereo images are degraded, resulting in the loss of 3D perception.
A lenticular array uses lens elements above the main LCD display to bend light to ensure the correct eye receives the light. With this technique, multiple sweet spots are possible along a horizontal viewing angle. Several "hands-on" videos of the pre-release Evo 3D show banding as the camera pans horizontally across the Evo 3D's screen, implying multiple sweet spots and therefore the use of a lenticular array for the 3D effect.
How 3D WorksEdit