720p vs 1080p – Technical Comparison
In this third part of the 720p vs 1080p guide we are comparing the two resolutions from a technical and theoretical perspective. We are going to see how the pixel size compares for screens of same size and also how the screen size compares for pixels of equal size. This is an easy way to quantify the differences between 720p and 1080p at a theoretical level.
Pixel Density for Screens of Equal Size
Considering three displays, each of them having the same size, this is how the pixel size and pixel density looks for three common resolutions. First is standard-definition 640×480 (480i or 480p) found in older CRT TVs, then 1280×720 (720p) found in HDTVs and finally 1920×1080 (1080p) which is the highest resolution found in a HDTV.
As you see, the pixel density increases with resolution, 1080p offering visibly more resolution over 720p. This translates into smaller pixels (dots) in the case of 1080p vs. 720p and 480i/480p. This is where viewing distance becomes important. If you are close enough to distinguish the pixels (dots) that make up the image, you get the full detail of 1080p. However, if you are not close enough you will not see the extra detail but the same detail 720p would give you. If you are very far from the screen of your eyes are not that great, you might actually see the same amount of detail as on an old 480i CRT TV.
Screen Size for Pixels of Equal Size
If we would have three displays and the pixels that make up the display would have the same size, this is how the screen sizes would compare.
As you see, 1080p is larger than 720p and a lot larger than 480i. This translates into the ability to have a larger screen size and see more detail from the same distance. If for example you would be sitting at 15 feet away from an old 480i CRT TV and that would be the ideal distance for that TV, watching a larger 1080p display from the same distance would give you a bigger picture as well as more detail.
From the above pictures it is clear that 1080p offers almost twice the detail of 720p and more than four times the detail of an old CRT TV (tube). If you sit at the optimal distance from your 1080p HDTV and watch a 1080p Blu-Ray movie, you will be able to see more detail. However, in real life things are more complicated. You dont always watch 1080p Blu-Ray movies or you may not have the money to buy the HDTV that has the optimal size. In this case, just because youre not at the right distance or youre watching lower resolution content will make you miss that extra detail that comes in 1080p and see the same thing that 720p offers or worse.
Continue reading the next part of this guide – 720p vs 1080p – Factors Affecting Perception of Detail – where you can find out what factors affect your perception (screen resolution, screen size, viewing distance and content quality).
All 720p vs 1080p Guides
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