Image : http://www.flickr.com
The optimum TV screen size is directly related to the available viewing distance – but there are other factors as well that must be considered.
Viewing distance: Is it just a matter of personal taste?
Sit too close to the big screen TV and you will be able to see the image build-up structure – scanning lines or pixels forming the image – so distracting your attention and enjoy your home theater experience. But sittingtoo far away and lost the effect.
There are different opinions about the best way to determine the optimum TV viewing distance for a specific screen size. Just go to the movies and you will soon realize that everything is a matter of personal preference – some would sit at the back. Others would jump to the front row, because they prefer the larger picture and a wider viewing angle, while others would simply choose randomly located somewhere between these twoExtremes.
The truth is that there are no scientific rules her. This does not mean that there are no guidelines that you should follow when planning a purchase or a big screen would-be home theater room.
SMPTE Recommendations and the THX certification standards:
The Society of Motion Picture and Television Engineers (SMPTE) recommends that the screen size for home theater use should occupy a 30 degree field of view – the horizontal plan – for the audience.Alternatively, the ideal TV viewing distance should be that the screen width takes an angle of 30 degrees to the straight position.
These have been 30-degree viewing angle seems to have adopted widely regarded as the standard in home theater and film.
The SMPTE directive is also in line with the THX certification that the standards recommend that the rear row of seats should have at least a 26 degree angle, and advocates, while an optimalViewing angle of 36 degrees.
It is believed that within these limits is a better perspective of the viewer get lost in the action movie itself.
Vision System limitations:
It is also the question of TV viewing distance on visual acuity. This does not represent the optimum viewing distance – but it refers to go to the maximum viewing distance of a few details about the image is lost.
Technically speaking, visual acuity is a measure of the Eye spatial resolving power and indicates the size of the angle to the smallest detail that a person can solve the visual system. A person with 20/20 (or 6 / 6 when expressed in meters can solve) normal vision of a spatial pattern from a perspective of one minute arc angle ie 1/60th degree of self to the eye when viewed at 20 feet away. In other words, a person with normal 20/20 Vision is capable of identifying an object with a height of 1.76mm at 20 feet is capable of.
With regard to the> TV viewing distances, these represent the border, some of the display window will no longer be resolved by the viewer vision system.
So how does all this translate into practice?
A few rules-of-thumb to help put into practice, the above-mentioned guidelines. These rules for viewing distance to screen width, not diagonally across the screen and therefore apply to both 4:3 and 16:9 display formats.
A general rule for TV displayDistance based on the SMPTE and visual acuity is the guidelines that the nearest TV viewing distance between you and your big screen TV should be about twice the screen width is limited (to be precise 1.87 x screen width for a circular circumferential angle of 30 degrees) , while the furthest distance, not more than five times the width of the screen.
This rule of thumb should give you a fairly good approximation for your TV viewing distance. It is not necessaryrepresent the ideal home theater viewing distance, but the limits within which your TV viewing distance should theoretically from the trouble zone.
In other words, more than twice the width of the size and the image scan lines, points and other video artifacts will be visible too intrusive – which spoil distractions that you will be movies. Move further away than 5 times the screen width and your vision system will no longer Be able to resolve all the details of the image.
But …
It is also important to recognize that these maximum and minimum viewing distances in the light of the video signal definition should be considered.
A fully resolved high-definition TV (1080i, 1920×1080) supports a closer viewing distance than standard analog TV. Thus, while twice the screen width would be the ideal TV away just for an HDTV display, it would be a little too close for standard –> TV, in the case, three times the screen width would be the better choice.
The five times the screen width than the maximum visibility, while more than adequate for a standard analog TV picture is a bit too far away for a support person to the smallest detail of an HDTV picture – a three to four times see the screen width is a practical limit to the maximum viewing distance in the case of HDTV.
These rules-of-thumb work best with largeTV sizes in the range of 42-inches and above.
When it comes to the use of regular size standard definition analog TVs in the home theater, ie up to 36 "/ 40" diagonal, the optimum viewing distance is between 8 feet and 12 feet. TVs smaller than 36-inches Aren 't large enough to have qualified for home theater use, the smaller screen size is not the desired effect on the viewer.
Vertical viewing angle and screen height:
Foroptimal representation of the viewer's eyes should be level with the center of the screen.
Maximum vertical viewing angle: In the home theater set-ups in case this is not possible, the SMPTE guidelines suggest that the maximum vertical angle should be measured to the uppermost part of the projected image on the seated eye height from the front row middle seat can not be than 35 degrees.
This does not represent the optimum viewing angle, but the limit, from which the viewerare at an increased neck strain.
This maximum vertical angle limit is always from the front row, because these are measured by the extreme angle.
Minimum angle: Even if it does not appear to be a specific SMPTE or THX guidelines in this regard, but studies have shown that when the screen size takes less than 15 degrees vertical field of view, the viewer than the small picture is displayed.
Practical considerations:
In a typical homeTheater Set-up, you do not have to make really about neither the maximum vertical angle worry, do not do well on the minimum vertical angle of view for an effective cinema.
If one of the recommended TV viewing distance of twice the screen width to keep (as set forth in detail the top of the SMPTE Directive of 30 degrees horizontal field of view), you would automatically meet the minimum angle. The reason is that there is a fixedRelationship between screen height and width to your home theater screen aspect ratio of either 16:9 or 4:3.
And more than that would be in a typical home theater setup, it is very difficult, the maximum vertical angle from which you are subject to an increased neck strain is exceeded.
Considering that most home theater rooms are approximately 10 feet (3m) is high, the resulting vertical viewing angles well into the normal maximum of 35 degrees in the detailedSMPTE guidelines – is everything you need to do only twice within the screen width guideline for the distance of the viewer to stay.
