» 1080p vs 720p or Full HD vs HD Resolution

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March 28, 2008

1080p vs 720p or Full HD vs HD Resolution

The 1080p vs 720p resolution decision [(1,920 x 1,080 pixels) vs (1,280 x 720)] should be made with an appreciation that resolution is not the only factor contributing to picture quality. In fact, resolution comes fourth in a recent SMPTE (Society of Motion Pictures and Television Engineers) study which ranked contrast ratio, color saturation, color temperature or greyscale ahead of it in ranking picture aspects the human eye sees in order of importance.

Two factors influence which resolution is more appropriate namely,

Screen size and
Viewing distance.

In general terms, the closer you sit to the on-screen image the more detail you can see as the image fills more of your field of vision. So the closer you are getting to the display/screen the higher the resolution should be getting to maintain picture quality. Moving away from the display/screen reduces the discernible difference between resolutions eg. 1080p vs 720p.

Below is a table matching up various screen sizes with the optimum viewing distances for 720p and 1080p resolutions.

Screen Size (diagonal)	1080p Resolution optimum viewing distance	720p Resolution optimum viewing distance
32 inches	50.21(4.2 feet, 1.3m)	75.31(6.3 feet, 1.9m)
42 inches	65.89 inches (5.5 feet, 1.7m)	98.83 (8.2 feet, 2.5m)
58 inches	91.01inches (7.6 feet, 2.3m)	136.51(11.4 feet, 3.4m)
100 inches	156.9inches(13.0 feet,4.0m)	235.34(19.6 feet, 6.0m)
120 inches	188.26 inches (15.7 feet, 4.8m)	282.35(23.5 feet, 7.2m)

A chart of optimal viewing distances in one inch increments is available from HDGuru.

1080p vs 720p Choice for Front Projectors

From the table above it can be seen that the optimum viewing distance for common projected images sizes (100 and 120 inch diagonal) the optimum viewing distance is going to be outside the home theater room. In fact, you even need a large home theater to sit at the optimum viewing distance for 1080p – there is a case for even higher resolutions to be available. So for optimum viewing, you need to purchase a 1080 resolution projector and sit a good distance from the screen.

Keep in mind though that if you choose 720p and are not sitting at the optimum recommended distance then the picture quality is only going to be slightly reduced not vastly reduced. Both 1080p and 720p can deliver excellent picture quality.

1080p vs 720p Choice for HDTV

While you could consider what consider what video sources you might have available (eg. Sony Playstation 3 and Xbox 360 have 1080p games) or the advantage of selecting 1080p to future proof your situation, for determining if 1080p will have any visual advantage over 720p have a look at the following simple chart from Carlton Bale. The chart shows how close you need to sit to be able to detect the benefits of a higher resolution screen. For an answer see where your likely seating distance will fall given your television room layout.