Best 3D TV Screen Size and Viewing Distance

Is 1080p really necessary or is 720p going to give me as good an experience? Should I spend money on a larger screen or getting a 1080p 3D TV? How far should I sit from the 3D TV that I purchase to get an immersive experience? If these are some of the questions you’d like answered, then this guide to choosing the optimal screen size and viewing distance for your 3D TV will help you immensely.

Optimal TV screen size, display resolution and viewing distance form the “Holy Trinity” when it comes to successfully setting up your 3D Home Theater. It is important to realize right from the beginning that there is a very close interplay between all three factors and that one has to take a holistic approach to determine the optimal setup for their 3D Ready home theater system. The manufacturers will have you believe that bigger numbers are always better…that 1080p is always better than 720p and buying a 70 inch HDTV is always better than buying a ‘puny’ 42 inch HDTV. Unfortunately, this is far from the truth and you can save a lot of money by wisely choosing the optimal 3D TV for your setup, while accounting for the constraints imposed by your budget. Before I jump into the guidelines for choosing an optimal screen size and viewing distance for you next 3D television, let me go over the basic factors that affect your 3D home theater experience. If you understand these, it will go a long way in helping you make an informed decision regarding the best 3D TV size for your requirements.

Field of view of your 3D TV

The field of view for a TV refers to the angular extent of the TV display from the viewers  perspective. To put it more simply, it relates to how large a fraction of the total view of the viewer the TV screen occupies. This implies that one can increase the field of view by either 1) Increasing the size of the 3D TV screen or 2) By moving closer to the TV screen.

THX recommends that for optimal viewing, the field of view for a home theater setup should be larger than 36 degrees (meaning a total FOV of 36×2 = 72). Thus in any THX certified theater, a viewer in the last row of the theater would still experience a field of view of 36 degrees. While there is no established upper bound on the maximum field of view, it is obvious that a field of view of 180 for a TV screen (squash your face right into the screen!) would be exceedingly uncomfortable and induce nausea and disorientation. The upper bound for maximum field of view is around 70 degrees (total FOV of 140 degrees), which corresponds to the maximum field of view inclusive of peripheral vision that we can typically view. The image below helps explain this concept. The blue line indicates a FOV of 50 degrees (100 degree total on both sides) and corresponds to what we can comfortably take in whereas the red line corresponds to an FOV of 60 degrees which takes into account what we can also register in our peripheral vision. In our opinion, you are better off aiming for an FOV of 50 degrees to 60 degrees for a truly immersive 3D experience. Trying to hit an FOV of 70 is a bit too extreme and will be especially ugly if you are viewing anything but 1080p content (more on that later).

What field of view is best for a 3D TV?

In the case of 3D TVs, it is very advisable to try and maximize your field of view so as to enable a truly immersive 3D experience. If you stop to consider your 3D experience in theaters (for example Avatar in 3D), part of what makes the experience so real and exciting is the sense of immersion you experience while watching the movie. The large field of view afforded by theater screens plays a big role in bringing this experience to the viewers. A large field of view (ie larger screen or sitting closer to the TV) is very advantageous when it comes to a 3D TV and you should aim to maximize your field of view when it comes to your new 3D home theater system.

Viewing distance and 720p vs 1080 for 3D TVs

The question of 3D TV resolution is a very important one and is closely related to our previous discussion on the optimal field of view for a 3D TV. Check our detailed guide on 720p vs 1080p 3D TVs for more information, but we will summarize the key points here to help you understand what resolution will work best for your requirements.

As you already know a 1080p image has much greater resolution than a 720p image. However, this extra resolution and detail has no meaning if you are sitting so far away from the screen that your eye cannot resolve this picture detail. This has to do with what is called “visual acuity” or the resolving power of the human eye. If we are sitting too far away from the TV screen, then our eye is incapable of resolving each separate pixel in a 1080p display and adjacent pixels tend to blur together. In such a setting, the viewer will be hard pressed to tell any difference between a 720p and a 1080p TV screen. This is exactly why you shouldn’t blindly (pun intended ) go and buy a 1080p display without taking into consideration your home theater setup, and how far you plan on sitting from your television display.

On the flip side, if you do have a 720p display but you are sitting close enough to your TV screen that you can clearly resolve each pixel, then 720p will look a bit blocky or pixilated and you will greatly benefit from the added resolution that comes along with a 1080p display. The one advantage that 1080p has over 720p when it comes to 3D TVs is that if you do in fact try to increase your field of view to the recommended numbers (36-50 degrees), then you HAVE to have a 1080p display so as not to be affected by pixelation issues. This is discussed in greater detail in the *LINK*720p vs 1080p 3D TV guide. The figure below also shows that IF we are indeed able to ensure an ideal viewing distance from a TV screen, then 1080p resolution is superior to 720p as it allows us to sit closer to the screen without any adverse affects from picture pixelation, etc.

Optimal Screen Size for best 3D Experience

When it comes to your 3D TV, the ultimate goal is to maximize your field of view (within reasonable limits of course) for an immersive experience while also making sure that you are not too close so as to be able to observe pixelation and blockiness in the videos on your TV screen. Thus, your viewing distance, Display resolution and Screen size are all related when it comes to deciding upon an optimal configuration for the best possible 3D experience. The section below will give you a good rule of thumb, and some ideas regarding the best screen size, resolution and viewing distance for your 3D TV setup.

Screen Size and Viewing Distance for 3D TVs

As mentioned above, the recommended viewing distance is affected by the resolution of your TV display. As a rule of thumb, if you multiply the diagonal width of the TV screen by 2.3 for 720p displays and 1.56 for 1080p displays you will get the optimal viewing distance in terms of visual acuity. What this means is that at this distance you will be taking the most advantage of the clarity afforded by the enhanced resolution of the display. If you move closer than this distance, you might start to notice some pixelation artifacts whereas if you moved significantly further back, then you would lose the extra detail afforded by the increased screen resolution.

On the other hand, as mentioned above, one would also ideally like to maximize the TV field of view for an immersive 3D experience. If we were to try and achieve a 70 degree field of view ( a bit extreme, but the maximum suggested FOV for a TV) then you would want to multiply the screen diagonal size by 0.63 (same for 1080p and 720p) to get the minimum allowed viewing distance. As you can see, the 1080p multiplier of 1.56 allows you to be closer to this minimum viewing distance thus enabling you to maximize your field of view while still having a good quality image, and thus the best 3D experience possible. If you have the flexibility in your seating arrangement, I would recommend playing with finding a sweet spot between this 0.63 and 1.56 multiplier (in the case of 1080p) TVs for your ideal viewing distance.

HOWEVER, and this is very important to note, there is a good chance that due to constraints of your room shape/size as well as your budget, you might not be able to achieve this target distance of 1.56 times the screen size viewing distance that is recommended for a 1080p display. In that case, you will be better off spending the extra money on a larger 720p screen than a 1080p display.

The table below should give you a rough idea of the suggested viewing distances for both 720p and 1080p 3D TVs. Keep in mind that these aren’t set in stone and you could always be flexible with the numbers. Just make sure that you don’t waste your hard earned money on a 1080p display if for the screen size of interest, your viewing distance is close to the one suggested for the 720p display. If you would like some exact numbers, then be sure to download Carlton Bale’s excellent HomeTheater Calculator (Excel File). The calculator should let you calculate a number of parameters and help you fine tune your decision and setup based on your desired 3D television screen size and resolution.

3D TV Size (Diagonal – inches)	Optimal Viewing Distance 720p (inches) – 2.3x	Optimal Viewing Distance 1080p (inches) 1.56x	Closest possible Viewing Distance 70 Degree FOV (inches)
42	97	66	26
50	115	78	32
55	127	86	35
60	138	94	38
65	150	101	41

Summary – Lets keep it simple

There was a lot to digest in this guide, but at the end of the day all you really need to take away from this is the table above. If you want the best possible 3D viewing experience then you should aim to get as close as 1.56 times the screen diagonal size of a 1080p 3D TV. In fact, you might want to try pushing the viewing distance down some more to find your sweet spot for the most immersive 3D experience. However, this is most likely not something that is possible for everyone out there as we usually have budgets and other considerations (can’t have chairs in the middle of the room just to hit the sweet spot for viewing distance). For those that are unable to hit this sweet spot, you should not be disheartened because you can still achieve a great 3D experience. Just try to maximize your field of view for your budget and make sure you don’t waste money on a 1080p display if the seating distance that you are constrained to negates the enhanced resolution afforded by a 1080p 3D TV.

Questions and Comments?

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