Aspect Ratios: What Are They And What Do They Mean?

Aspect Ratios: What Are They And What Do They Mean?

Last week, we delved into the messy, manic world of codecs, containers, compression, and just about every other technical fun fact imaginable when it comes to online business video. This week, we’re going to spend a bit of time focusing on aspect ratios, because, well...they’re really fun. The most common television aspect ratios are listed in the image below, and similar aspect ratios (like the dark green widescreen family) are color-coded and listed together along dotted lines.

Aspect Ratios: What Are They And What Do They Mean?

The Most Common Aspect Ratios

Do you actually need to know the difference between each of these aspect ratios? Absolutely not. You won’t use most of them (ever). All you really need to know is that the most common aspect ratios are:

4:3 - normal
16:9 - widescreen

As you can see, each of these aspect ratios has several different associated resolutions. 4:3, for example, ranges from 320x240 to 2048x1536, while HD includes 1280x720 and 1920x1080. That’s because an aspect ratio is just a ratio, which means it’s a comparison of two numbers That’s because an aspect ratio is just a ratio, which means it’s a comparison of two numbers. Different resolutions can have the same aspect ratio if the ratio of an image’s width and height are the same.

800x600, for example, simply means 800 pixels by 600 pixels, and 4:3 is just the lowest integer representation of those two numbers when divided by a common factor (800/200 = 4 and 600/200 = 3).

Understanding that “4:3” really means 4/3 is important because, oftentimes, aspect ratios are also represented by their decimal counterparts. 4/3 = 1.333333333…, so sometimes a 4:3 aspect ratio is shown as “1.33.” Can you tell that 4/3 and 1.33 are the same value? Probably not. That’s why it’s also useful to recognize aspect ratio by both their names.

17:9 = 1.89
16:9 = 1.78
5:3 = 1.67
8:5 = 1.60
3:2 = 1.50
4:3 = 1.33
5:4 = 1.25

Far more interesting than the difference between each aspect ratio, however, is the story of how all these different aspect ratios became widely used in the first place. FilmmakerIQ released a fantastic video earlier this year all about the history of aspect ratios and it goes into great detail about how we went from 4:3 to 16:9. I’ll try to stay concise and highlight the most interesting points in this post but here's the video for your viewing pleasure:

How We Learned to Stop Caring and Love Widescreen

Basically, it all started when Thomas Edison invented the kinetoscope in 1888. What is a kinetoscope, you ask? This thing:

Aspect Ratios: What Are They And What Do They Mean?

Of course, Edison also hired a lab assistant to help him develop kinetoscope film. The guy’s name was William Kennedy Dickson (definitely an 1800s name), and he first displayed a viewable “video” using perforated 35mm film with a 4:3 / 1.33 aspect ratio. Why did he choose 4:3? We’re sure the answer is buried away somewhere in an old, waterworn journal beneath the floorboards of a rowhouse in Edison, NJ. But for now, we have no idea.

In any case, 4:3 stuck, most certainly because of Edison’s dominant presence in the early days of the 20th century film industry. In 1909, the Motion Picture Patent Company declared that Edison’s 35mm, 4 perforation image at .95 inches by .735 inches (4:3) was the standard across the known and unknown world.

Aspect Ratios: What Are They And What Do They Mean?

In 1929, synchronized sound was added to film reels as a strip that had to be added next to the images. This slightly altered the aspect ratio, and in 1932, the Academy of Motion Picture Arts & Sciences declared that film should maintain a 1.37 aspect ratio (rather than 1.33). This was known as the “Academy Ratio”, and it remained standard until the 1950s.

That’s when a film shooting technique called “Cinerama” was developed in 1952 to shoot widescreen for the first time. Cinerama was really complicated and somewhat ahead of its time - it used 3 cameras to shoot 3 6-perf images side by side to create a combined 147 degree panoramic field of view. This resulted in a whopping 2.59 aspect ratio, which is far larger than the more common extreme, 1.89.

But because it required shooting with 3 cameras and projecting with 3 cameras (on top of the curved screen that had to be used in theaters), Cinerama never took hold. It was just too expensive, and ultimately the technology was only used to create 2 feature films, including 1962’s How The West Was Won.

Time to back up a little. In April 1953, a film studio called Paramount released the first flat widescreen video film in a much more familiar 1.66 aspect ratio. This film, which you’ve probably never heard about, was called Shane.

Shane wasn’t relevant in any way, really - but it was significant that Paramount had developed a proprietary flat widescreen format that only required one camera, and that they were damn proud of it (you’ll see why in a bit).

Back in the 1920s another guy named Henri Chretien had invented something called an “anamorphoscope”, which used a specialized lens to shoot flat widescreen. Called “Cinemascope”, this technique used a 2.35 aspect ratio, which was almost as wide as Cinerama, and was compatible with traditional 4-perf film. Seeing Paramount’s success with their own widescreen technique, most studios quickly made the switch from traditional film to Cinemascope. One of the first films shot using Cinemascope was The Robe (1953).

Paramount wasn’t to be outdone, though. They quickly developed VistaVision in response to Cinerama. Vistavision was the first film-shooting technique to turn film strip sideways (because that way each image could be wider), and record 8 perforation images at 1.85 aspect ratio. The first VistaVision film was White Christmas (1954), but the most famous are The Ten Commandments (1956) and many of Alfred Hitchcock’s films, including To Catch a Thief (1955), Vertigo (1958), and North By Northwest (1959).

By the 1960s, the “Widescreen Wars” were in full swing. Techniques like Superscope, Cinemiracle, Technirama, and Vistarama all came and went. Another really popular format that appeared during this time was Todd AO created by Mike Todd at American Optical Company. Todd AO was a 70mm format that used a 2.20 aspect ratio and was use to shoot nearly all of the Rodgers & Hammerstein film adaptations, including The Sound of Music (1959).

Lots of other major, Academy Award-winning motion pictures used fad shooting formats, including Ben Hur (1959), which was shot using Panavision’s 70mm method, and Lawrence of Arabia (1962), which was shot in Super Panavision 70 at a 2.20 aspect ratio. As you can see, The Aspect Ratios had quite a colorful history.

The Aspect Ratios’ Greatest Hits

Original Silent Film: 1.33
Academy Ratio: 1.37
Cinerama: 2.59
Vistavision: 1.85
Cinemascope: 2.35
Todd AO/Super Panavision 70: 2.20
MGM 65: 2.76

So...what does all this have to do with Television?

Very little, actually. Turns out that while the Widescreen Wars were going on in Hollywood, TVs more or less stuck to 4:3 convention. Eventually, in the 1980s, a guy by the name of Kerns H. Powers suggested that 16x9, or 1.78, should be used as a standard for widescreen because it was the median aspect ratio between 4:3 and 2.35, the two extremes of the day. His suggestion stuck, and 16:9 remains the aspect ratio in use for the most popular forms of widescreen, including 1080 and 4K.

Widescreen’s increasing popularity in the 21st century is really just a resurgence of the Widescreen Wars that began more than half a century ago. And it makes sense, since the human eye is naturally “widescreen”, so to speak. IMAX is the evolutionary descendant of the now-extinct Cinerama format, and we have since learned to accept the standardized aspect ratios of 4:3 and 16:9 and move on to worrying about bigger things.

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About Our Contributing Author - Han-Gwon Lung
Han Lung writes for Vidaao, a video production marketplace that connects marketing teams with creatives and provides them a collaborative project space.



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What do you think? ▼
  • Bill Cobb

    Thank you so much for this helpful instruction and I have a question. If I'm editing a video on my iPad 3 via iMovie app for upload to YouTube and I want to send that render to my camera roll to upload manually to YouTube, should I render it 720p or 1080p for that perfect aspect ratio...or does it really matter? On YouTube, does it matter if I uploa 720p or 1080p, they're both "HD" right? For the same video, the 720p render is 97.1mb and for 1080p it's 192mb. Naturally, Youtube probably wants the smaller file uploaded. And, I can decrease the size with Handbrake.
    Thank you so much.