Television Viewing Distance

Viewing Distance

One of the most difficult aspects of picking out a television is how big of a television should you get for your living room. There are two factors that determine the best size of the television:

The minimum resolution for an individual viewer
The number of people that want to view the television.

The minimum resolution for an individual viewer is determined by the screen size, viewing distance and the limitations of human vision. Starting with vision limitations, we have different qualities of vision depending on if we are viewing color or black and white. Since the rods are smaller because they see a wider range of color, they define the eye's angular resolution. Someone with 20/20 vision has an angular resolution of 1 arc minute or 1/60th of a degree.

So that we don't see pixels on the television, the pixels need to be smaller than what the human eye can resolve. The Kell factor defines that you need 10 pixels for every 7 picture elements. Thus, depending on the distance that you are viewing ... I have to go to work now Mike.

Viewing Distance in Feet	Visual Acuity (1/1000th of an inch)	Pixel Height ( 1/1000th of an inch
0.5	1.7	2.5
1	3.5	5.0
2	7.0	10.0
3	10.5	15.0
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

0.5 1.7
1 3.5
2 7.0
3 10.5
4 14.0
5 17.4
6 20.9
7 24.4
8 27.9
9 31.4
10 34.9
11 38.4
12 41.9
13 45.4
14 48.8
15 52.3
16 55.8
17 59.3
18 62.8
19 66.3
20 69.8

As Figure 5-3 from Broadband Entertainment shows, the human eye has different sized receptors for black & white and color. The rods of the eye are smaller and let us see about 1 arc minute of resolution. For more on rods and cones, go here.

For more on rods and cones, go here.

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HDTV - Spatial Resolution - Temporal Resolution - Aspect Ratio
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Television is a very complex topic. If you would like to add some comments, corrections or additional topics, please e-mail info@broadent.com.