When Widescreens Work:
How to Choose the Right Aspect Ratio
Year after year, I'm asked by home theater newbies on the ProjectorCentral Forums some form of this question: Should I go with a 2.35 aspect ratio screen for my first projection setup? The answer is the all too typical: It depends! Most of the time, though, the best answer for many is not to use a 2.35 screen for their debut system. If in doubt, at all, it's better to go with a 16:9 (1.78) screen and pair it up with your 16:9 projector.
For the uninitiated, the aspect ratio of a projection screen, or any screen for that matter, is the ratio of the width of the screen to the height of the screen. Before the days of flat-screen displays, the old CRT tube-type televisions had an aspect ratio of 4:3, or 1.33 (4/3=1.33). This was a standard across the industry and all television shows were presented in the squarish 4:3 aspect ratio, as were many movies. As we moved into the era of high-definition television, the standard changed to the wider 16:9 or 1.78 format. So, a screen 16 inches wide would be 9 inches tall. A projection screen 178 inches wide would be 100 inches tall...with that 16:9 aspect ratio always maintained. This is now the standard for televisions throughout the world. Every LCD TV at your local big-box store is being sold in the 16:9 aspect ratio, and the vast majority of computer monitors and laptop displays use this screen ratio as well.
The Wider Widescreen
So, what's the hype with front projection and 2.35?
First, let's get a bit more accurate with our language, as many blockbuster films are actually shot in the 2.39 aspect ratio, often called 2.40 by many, but still used interchangeably with 2.35 or "anamorphic." This is a screen ratio that is about 33% wider than the 16:9 aspect ratio. So, while 16:9 was often called widescreen, 2.35 is an even wider widescreen. This aspect ratio is selected by many movie studios to present films with a very wide viewing area that displays a more artistic viewpoint of the landscape and the people within. Most major cinematic films are shot in this aspect ratio. You can see in the image below the dramatic difference in presentation compared with the truncated 16:9 image of the same landscape shown above.
"Great! So, that's perfect for my theater, I will get it!" you think to yourself. "I've certainly seen a lot of advertisements and home theater photos online showing that type of screen in all the best setups."
But this is where it all falls apart for many new projector buyers. Many of those really nice home theater setups have tens of thousands of dollars invested in the room and the equipment in use. If you are on a far more limited budget, which is almost always the case, then care must be taken before jumping into a setup which may not be at all ideal for your specific theater.
The room itself matters because most rooms have a blank wall that is the location where the screen will go. When you look at the wall, you can tape off or visualize different screen sizes on that wall. It is typical that most rooms aren't terribly wide, and most walls in the United States are about 8 feet tall. So, the first thing to do is measure the wall and see how much width you actually have to work with for your front projection screen. Keep in mind that speakers often need to go to the left and right of the screen, and that another speaker typically sits under the center of the screen for the center channel audio. On a wall that's 12 feet wide (144 inches), you may only have about 10 feet, or 120 inches, of width that the screen can fit into. A nice fixed-frame screen may have a 4-inch wide frame around it, reducing the actual screen width to 112 inches.
In the 1.78 aspect ratio, a screen that is 112-inches wide will be 63-inches tall. In the 2.39 aspect ratio, a screen 112-inches wide is just 47 inches tall. When you look at your wall, do you have 16-inches to accommodate the taller 1.78 screen? That's 8-inches on both the top and the bottom added to screen size. In fact, most people do have plenty of room to handle the height, but often don't have the width they need to go wide enough to achieve the desired impact. Others may have a very wide room but have some architecture or furniture that severely impacts the height they have available to them.
Constant Image Height
Okay, let's say you are in a setup where the width works, and you really want to go with a wider screen. So, we come to the next part, which is the budget. You see, all home theater projectors these days are designed around the 1.78 aspect ratio. Just like you can't buy a TV these days which isn't 1.78, you can't buy a home theater projector which isn't 1.78. When you watch TV at night, all television broadcasts are 1.78. All video gaming is 1.78. Even though the movie itself may be 2.39, all movies are presented to you in your home as 1.78. This means that even if you really want a 2.39 image, there will still be a fair bit of viewing material that needs the projector to fill a screen with that 1.78 aspect ratio. Whatever projector you buy will have to be able to switch from the 2.39 aspect ratio to the 1.78 aspect ratio while maintaining the image with the full height of the screen.
This can be done two ways.
First you can buy an expensive add-on lens. Remember when I said that you were sold on the wider aspect ratio because of those nice theaters? Well, those people probably purchased a really expensive 1.78 projector, then matched it up with an adapter lens, likely on a motorized sled, that slides in front of their projector and converts the 1.78 output to 2.39. This lens is called an anamorphic lens. It's a common feature in high end home theaters and one of the major manufacturers in the industry, Panamorph, has their least expensive lens starting at a price of almost $7,000. A good used lens may be several thousand dollars. An anamorphic lens is the ideal option because, when mated with a projector that has an anamorphic viewing mode, it eliminates the black letterbox bars from the image before it's projected up and uses all the pixels in the projector's imaging devices to retain the highest level of brightness. But if your total budget, including sound, is just a few thousand dollars, then getting an anamorphic lens is likely out of the question.
This leaves the second, and increasingly more common option of using a projector which has enough zoom range to fill the 2.35 screen fully, or fill the 1.78 area within the 2.35 screen when the content calls for that. When the projector is zoomed to fill the full 2.35 screen, letterbox bars placed in the movie to accommodate a 1.78/16:9 screen bleed off the top and bottom, allowing the active part of the widescreen movie image to fill the full screen height and width. Conversely, when the projector is zoomed to fill the full height of the screen with a 1.78 image, you're necessarily left with some unused area on the left and right. (See more about letterbox and pillarbox bars below). This zoom procedure works well enough, though when the full 2.35 screen is being used, some number of pixels at the top and bottom of the projector's imaging chips are still reproducing the letterbox bars, which results in a modest loss of brightness compared with using an anamorphic lens. Of course, there is also some marginal loss of brightness associated with moving the zoom from a wide position to a more telephoto position—as well as with sliding an anamorphic lens into the light path if you do use one.
Using the so-called "zoom method" requires that you adjust the zoom on the projector from one position to the other anytime the switch needs to be made. This can be a really big hassle for most people and certainly not something that a typical user wants to do in day-to-day use. Fortunately, there are a few projectors on the market with motorized lenses that feature memory presets that allow you to switch between different lens settings at the touch of a button or two. For example, Epson currently has the reasonably priced Home Cinema 4010, 5050, and 6050 models with this feature. Some of JVC's and Sony's current projectors, for a bit more money, also feature motorized lens presets.
If you go this route, measurements need to be made, checked, and double-checked to ensure that the projector properly fits the space to allow the zoom method to work. Returning to the example of the 112-inch wide, 2.39 aspect ratio screen, we know the image height is about 47 inches when viewing 2.39 content. Using the budget-minded Epson HC 4010 as an example, checking the projector manufacturer's or ProjectorCentral's throw distance calculator, we see that this projector can throw that 112-inch width from about 13 feet to 26 feet, lens-to-screen. But, to fill the 47-inch screen height with 16:9 content, the projector must be between approximately 10 and 20 feet. The crossover between those two ranges, then, requires the projector to be about 13 to 20 feet from the screen. Does this work for your room?
Black Bars: Can't Live Without 'Em
One of the big reasons that people love the idea of the 2.39 screen is that movies created and presented in the 2.39 aspect ratio won't show visible black bars above or below the image on screen (called letterboxing). All you will see is the movie, perfectly framed by your projector screen, just like in the movie theater. But, most content produced for 16:9 HDTV viewing, even many blockbuster movies originally created in a 2.39 format, won't be broadcast with black bars above and below the image. Therefore, when you switch to 1.78/16:9 viewing, there will be bars on the left and right side of the image. This is called pillarboxing. So while you can eliminate letterbox bars by using a 2.35 screen, you can't get completely away from some form of black bars or masking.
If your available wall really demands a 2.35 screen and the budget allows the use of an anamorphic lens, or the use of a projector with motorized zoom presets, then it's hard to beat the immersion and the home theater feel that a 2.39 setup can deliver. Yet, for those just looking to get their feet wet for the first time in the front projector and home theater world, relying on the industry standard 1.78/16:9 aspect ratio is a much safer way to go and a much easier setup to work with as it already matches all the other TVs you own in your home and fits naturally with the content you already have. The biggest downside is when you watch 2.39 aspect ratio widescreen movies, there will be black letterbox bars above and below the image—just like you've seen for years with widescreen movies on your 1.78 television. The only difference is that, even with a 1.78 screen, you'll be enjoying a much larger and engaging front-projected image that beats a typical flat-screen hands down every time.
To sum up, here's a list of pros and cons to help you decide what screen aspect ratio is right for you.
Pros of a 2.39 aspect ratio setup:
- Most accurate representation of the movie theater experience at home
- Fits some walls better than screens with a 1.78 aspect ratio
- No letterboxing with 2.39 films
- With an anamorphic lens, the maximum brightness possible is achieved with widescreen content
Cons of a 2.39 aspect ratio setup:
- More expensive to setup than a 1.78 home theater
- Requires much more planning and thought to get the setup right
- May be wasting available height which the projector could be using within the home theater
- Pillarboxing will occur when viewing 1.78 content on the 2.39 screen
- Need to change lens preset, or move an anamorphic lens, when switching between 2.39 and 1.78 content
- Some movies have subtitles which are below the 2.39 viewing area, putting it below the bottom of the screen
Pros of a 1.78 aspect ratio setup:
- Very straightforward setup that matches the aspect ratio of the projector you are buying
- Less expensive to set up
- Screen size maximizes both the available width and height in most rooms
- No pillarboxing with 1.78 content
- No need to adjust lens or zoom when a movie switches aspect ratio
- Subtitles will always appear on the screen where they were meant to appear
Cons of a 1.78 aspect ratio setup:
- Not as immersive with 2.39 movies. The largest content you will be presenting will be 1.78 HDTV content
- 2.39 movies will have letterboxing or black bars above and below the movies as they play
- May not always use the available width that a wall may have to offer