There are currently two technologies for producing 3D on HDTVs – passive (polarisation) and active (liquid crystal shutter). Of the larger HDTV manufacturers, Samsung, Sony and Panasonic are using active 3D technology while LG and Vizio are using passive 3D technology. While it’s fairly clear to anyone viewing the two technologies side-by-side that the active 3D technology produces a better quality picture there are other factors which make the choice more one dependent on circumstances, cost and personal preferences.

Active Shutter 3D Technology

An Active 3D HDTV displays alternating frames shot with a slightly different perspective. Utilizing a frame synchronisation beam from the HDTV, the liquid crystal shutter lenses of the 3D glasses ensure that each alternating frame is shown to either the left or right eye creating the illusion of 3D. The resolution displayed is the full resolution of the HDTV (1080P) and so is termed Full HD 3D.

The 3D shutter glasses require batteries to power them, cannot have curved lenses and are comparatively heavier (not an attractive look really). Because electronics, batteries and LCD shutters required, Active 3D glasses are more expensive than the simple polarized lens glasses required for passive 3D.

Because they are heavier, active shutter 3D glasses are less comfortable especially – if worn for long periods. As well as being expensive, active shutter glasses will unfortunately only work with the brand of HDTV they were purchased for. They are also more susceptible to damage than the passive 3D glasses.

Passive 3D Technology

Passive polorization 3D technology is the same technology used for 3D in cinemas which is why LG call it Cinema 3D. Passive 3D HDTVs have a polarized filter with alternating horizontal and vertical stripes. When viewed using 3D glasses with corresponding polarizing lenses alternate frames are displayed for each eye to create a 3D image. Unfortunately, passive 3D reduces the horizontal resolution of the 3D image by half turning 1080 lines down to 540.

In comparison to active 3D glasses, polorized glasses are lighter, have no electronics, are compatible with other brand HDTVs using the same technology and can be made with curved lenses to look more attractive. Passive 3D images are brighter than active 3D and so more suited to a light viewing environment.

Passive and Active 3D Technology Picture Quality Compared

Generally passive 3D looks less sharp than active 3D due to the reduced horizontal resolution. The most noticeable imperfections are jagged straight edges and blurring of fine textures. The viewing angle for active 3D is larger than for passive 3D while passive 3D produces a brighter image (when viewed though the glasses). While there is a noticeable difference in picture quality it is not so significant that it will drive consumers one way or the other.

Deciding between passive and active 3D technologies becomes a personal choice between the importance of performance versus cost.

If you find passive polarized 3D at the cinemas acceptable you are probably going to be OK with the same technology at home. It’s a valid choice if you want to avoid considerable expense for a larger number of glasses. There is also some advantage to choosing passive 3D if you will be watching your HDTV in a brightly lit room.

If you have little tolerance for blemishes in picture quality then active 3D is a better choice as long as you can cope with less comfortable and more expensive 3D glasses which require battery changes or recharging every 40 hours or so. Active 3D is also a better choice for large screen sizes (over 46 – 50 inches) as any imperfections will be magnified and more obvious. The higher cost of active 3D glasses is a crowd killer, but given they are far less attractive you may not want a crowd watching with you.