Projector Vs TV, How does a projector work?

Best projector screen size

One of the most important things to consider before buying a Projector is the size of the projected image you want on your screen or wall. The natural instinct of almost everyone is to have the biggest screen you can have. But the best size projector screen will depend on where your projector screen is and how far or close you will be sitting to watch it.

There is an optimum size for the projector screen depending on how far you sit from the screen. The best size projector screen for watching a projector for a long time without eye strain and headaches will depend on the angle the sides of the projector screen makes with your eyes. Both sides of the projector screen must be within the 'Visual Field of human eyes'. To quote from the reputed Sight Science website

What is the visual field?

The visual field is the area of your vision that you can perceive when you look straight ahead without moving your eyes or head. Within the visual field our visual quality is different, depending on the area- in the center of our view, where we fixate objects, text, faces etc. with our eyes, we see particularly sharp. Further to the sides we see more blurry (peripheral vision). In the periphery it is most important to notice movements, so that eyes and head can be moved into that direction.

Human field of view (FOV) for both eyes showing far, mid- and near peripheral vision, macular, paracentral, and central ... credit https://commons.wikimedia.org/wiki/File:Peripheral_vision.svg
Human field of view (FOV) for both eyes

Based on several studies by ophthalmologists and optometrists, it has been established that the best vision for humans with full focus is in the central field of vision or at the 'center of Gaze'. From studies by architects who specialise in the design of auditoriums and cinema theaters it has been established that for the best view of screens, it must fall within the human eyes Near Peripheral Vision or the vision area just adjacent to the center of gaze within an angle of 30° on either side.

Size of projector screen as per vision field
Size of Projector Screen

So for the best Projector Screen size, it must be within our Near Peripheral Vision, which is, at a 30° angle on either side from the center of our two eyes. The figure shown here (Not to Scale) represents this. The angle at the top of the triangle represents the view from our eyes and is 60°. Using our basic Geometry knowledge, this means that it is an equilateral triangle with each of the three angles in the triangle being 60° and all the three sides being equal. Using Pythagoras theorem we can calculate that the distance from our eyes to the base of the triangle, which represents the screen to be
= √¾ x base which works out to
Distance from eyes to screen = 0.866 x width of screen
Or Width of Screen = 1.15 distance
Instead of the width of the screen, it will be easier to work with the standard size of the screen which is its diagonal measurement. We know that the factor to convert the width of a 16:9 aspect ratio Projector Screen to its diagonal size is to multiply the width by 1.15. So in our calculation above, if we use the diagonal size of the screen, we get
diagonal size of screen = 1.15 / 1.15 distance
Therefore, Size of Screen = Distance of Viewing.

Incidentally, THX, considered the world's leading authority on developing Standards for high fidelity audio/visual reproduction for movie theaters, screening rooms, home theaters, etc. recommends the following for the best viewing distance / screen size

Divide the size of your screen by 0.84 (screen size is measured diagonally). For example, a 65-inch TV divided by 0.84 equals a 77-inch viewing distance (6.5 feet).
This value becomes about 20% more than my calculations done above, which means that you have to watch the screen image at 1/0.84 or 1.19 times the size of the screen. I feel THX recommends these values based on TV screen sizes and may not be practical for projector screen sizes. My recommendation, as a qualified Engineer with many years experience using projectors at home and doing a vast amount of research on the subject, is that, it is more practical to watch projector screens at about the same distance as the diagonal size of the projector screen. If you follow the THX advice and use it for projector screen size, then you will end up with tiny screens due to cramped spaces in normal homes.

Where to buy Home Theater Projectors and Projector Screens online

The best place to buy Projectors and Projector screens is the Amazon online store in your country. Amazon is best to buy online Projectors and Screens because not only are they very competitively priced, but you also have the assurance of service, and in the worst case, even return for a refund in case you are not satisfied.

Links for Home Theater Projectors

This is the Link for Home Theater Projectors from Amazon AUSTRALIA

This is the Link for Home Theater Projectors from Amazon CANADA

This is the Link for Home Theater Projectors from Amazon INDIA

This is the Link for Home Theater Projectors from Amazon UK

This is the Link for Home Theater Projectors from Amazon USA

Links for Projector Screens

This is the Link for Projector Screens from Amazon AUSTRALIA

This is the Link for Projector Screens from Amazon CANADA

This is the Link for Projector Screens from Amazon India

This is the Link for Projector Screens from Amazon UK

This is the Link for Projector Screens from Amazon USA

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