A Guide to Aspect Ratios in Film
Aspect ratios are an integral part of any film and choosing what film aspect ratio you want to use is a vital part of the filmmaking process. When shooting on film, the aspect ratio will influence what camera and film system you use. With digital filmmaking, there is flexibility to adjust your aspect ratio when editing, but it’s still important to know which you prefer before shooting so you don’t risk having to cut important information out of the frame or waste part of the frame with empty space.
Let’s take a look at what aspect ratios are, which ones are commonly used, and how you can decide the right one for you.
What is an Aspect Ratio?
By definition, an aspect ratio is simply the ratio of how wide an image is to how tall that image is. There are no specific units attached.
A standard high-definition television screen has a 16:9 aspect ratio. Old standard definition televisions had a 4:3 aspect ratio.
Aspect ratios are important for both still and video shooting. DSLR and mirrorless camera sensors typically have a 3:2 aspect ratio, meaning that video shot on them is almost always going to get cropped rather than use the full sensor. Even so-called “cropless 4K” will cut out the top and bottom pixels until it creates the necessary aspect ratio. Cinema cameras typically have sensors that closely match their highest resolution’s aspect ratio, often around 19:10.
As you can see, there are many aspect ratios. Fortunately, there are a handful of common aspect ratios used in filmmaking.
The Evolution of Aspect Ratios
Popular aspect ratios have changed a number of times over the history of film. To understand which will fit the aesthetic you’re going for, it’s helpful to look at how the major ones have evolved.
The Original | 4:3 (1.33:1) | 1890s
While our modern association with the 4:3 aspect ratio is rooted in pre-HD television, it goes back much further. When Eastman Kodak invented the first flexible film stock, William Kennedy Dickson and Thomas Edison used it to create and patent 35mm film rolls. Edison then adapted it for his Kinetoscope, the predecessor to the motion picture camera.
Edison’s patent standardized several characteristics including the perforated edges used to pull the film, the size of the film and the number of perforations per frame (4). In 1909, the Motion Picture Patents Company agreed to use Edison’s system as the “official” standard for motion pictures. Most of the evolutions and adaptations of film until the mid-1900s were based off of this original standard.
Academy Ratio | 1.375:1 | 1932
The first major change to motion picture film standards came as the result of a major evolution in movies: sound. In order to add the audio track, a thin strip of the film next to the images was utilized, which required shrinking the image frames.
The first versions of this resulted in a narrower 1.19:1 aspect ratio (the ratio recently chosen to give The Lighthouse its vintage look). However, the almost square image created some unforeseen problems in projecting the film.The solution to this was to shrink each image frame, using a larger gap in the film between frames to preserve the 4-perforation-per-frame standard. It resulted in a slightly wider 1.375:1 aspect ratio. The Academy Ratio was adopted by the Academy of Motion Picture Arts and Sciences as the new standard in 1932, and every studio film shot in 35mm from 1932 to 1952 used the Academy Ratio, including Citizen Kane and Casablanca. It’s also been used in modern films such as First Reformed and parts of The Grand Budapest Hotel.
Cinerama | 2.59:1 | 1952
Another innovation prompted the next change in aspect ratio, and that was the growing popularity in home television (and the resultant decline in cinema attendance). Because almost all motion pictures created up to this time were in a 4:3 aspect ratio (or the closely-related-enough 1.375:1 Academy Ratio), TVs were naturally built in the same aspect ratio. In 1952, in order to stand out, the Cinerama system combined three 35mm images side by side on a curved screen to create a combined 2.59:1 aspect ratio.
Cinerama was enormously popular, but also incredibly challenging. It required the film to be shot with a 3-camera rig that only worked with wide angle lenses and then to be shown with 3 precisely aligned, synchronized projectors. These limitations lead it to be used almost exclusively for documentaries and travelogues, though two dramatic films, The Wonderful World of the Brothers Grimm and How the West Was Won, were eventually made with it.
CinemaScope | 2.35:1 | 1953
Both the popularity and the challenges of Cinerama were immediately apparent, leading studios to look for ways to get widescreen capabilities without the three camera/projector system. The answer was French inventor Henri Chretien’s anamorphic lenses.
The anamorphic lenses squeezed the image horizontally while not affecting it vertically. This resulted in a squished image on film, but special lenses on projectors eliminated the distortion, showcasing a wider aspect ratio. These adaptations allowed the same film system (including both cameras and projectors) to be used – a much simpler and less expensive approach than creating a new film system from scratch.
CinemaScope was an enormous success, first used in The Robe and later in such movies as 20,000 Leagues Under The Sea and even for animated movies like Lady and the Tramp. Even more important than CinemaScope itself was the 2.35:1 aspect ratio, which continued to evolve into the modern widescreen cinema standard. You will often see arguments over whether 2.35:1, 2.39:1 or 2.4:1 is the “correct” widescreen cinematic aspect ratio, but the reality is that in practice these all refer to the same thing and are interchangeably used (though 2.39 is the most technically accurate ratio). Additionally, modern ultrawide displays are being marketed as 21:9 (though they are more accurately 21⅓:9) which translates to about 2.37:1, right in line with this ratio.
Anamorphic Lenses and Modern Cameras
Online you will often see people advocate for using anamorphic lenses to achieve a more “cinematic” look. But how does this work in practice with modern tools?
Many of the anamorphic effects can still be achieved. An anamorphic lens will still distort the image, creating a squeezed frame that fits more horizontal image onto the frame. In processing, your video editor will need to expand the footage back out to correct the distortion. Fortunately, most video editors can do that without any problem.
Some people will advocate for faking the anamorphic look. A wide lens and careful cropping can approximate the look, especially if you are shooting at a higher resolution than you are exporting so that you don’t lose important resolution.
But that method’s not perfect. There are some unique traits of anamorphic lenses that are difficult (or impossible) to achieve if you’re using a spherical lens. Some of the more easily observed traits include bokeh becoming vertically stretched in your final video and horizontal bands of light when you have bright flares in your frame. The less obvious trait is that anamorphic lenses give unique characteristics to the depth of field and angle of view.
In order to get the same horizontal field of view as an anamorphic lens, you would need to use a pretty wide focal length. Wide focal lengths naturally have wider depths of field and are prone to perspective distortion. If you want a close up of a face, a wide angle lens is going to distort the facial features. Anamorphic lenses let you have the characteristics of a longer lens (less distortion, shallower depth of field) while still seeing more horizontal area.
Is an anamorphic lens a necessary part of your kit? Not really, but it will give you some capabilities you won’t find anywhere else.
VistaVision | 1.85:1 | 1954
The success of Cinerama and CinemaScope kicked off a seeming stampede of new formats and aspect ratios throughout the 1950’s, perhaps the most innovative and experimental time period when it comes to aspect ratios.
Despite the success of CinemaScope, there were some challenges. Because of how the anamorphic lens distorted the image to fit the frame, which was then expanded back into shape, CinemaScope had a tendency to expand and exaggerate negative aspects of the film, such as unwanted grain. It also required specialized lenses on both the camera and the projector in order to distort and then correct the image.
To get around this, Paramount invented VistaVision. They essentially turned the 35mm film sideways and stretched the frames to 8 perforations per frame. One intermediate step between filming and presenting was to shrink the frames to fit onto standard 35mm, making it easily compatible with existing cinema projectors while still shrinking the visible grain.
Some of the more notable movies shot in VistaVision include White Christmas, The Ten Commandments, Taxi Driver and many of Alfred Hitchcock’s films including Vertigo and North by Northwest. Additionally, 1.85:1 is a very commonly used aspect ratio for modern cinema films that are not presented in “widescreen” (i.e., not 2.39:1).
Todd AO | 2.2:1 | 1955
Until this point, all of the film formats were largely based off of the original 35mm standard, albeit with modifications. First seen in 1955, Todd AO kicked off the first real attempts to increase the image quality by abandoning 35mm and using larger film stock, in this case 70mm film. Todd AO was used in films such as Oklahoma, Around the World in 80 Days, Sound of Music and Patton.
The biggest challenge with all 70mm projects was the significantly higher cost of both filming and showing 70mm movies. Even today, films shot on 70mm are frequently considered spectacle films, where the film process is sometimes as highly billed as the movie itself.
MGM 65 | 2.76:1 | 1957
MGM 65 wasn’t a frequently used format, but combined 70mm film with anamorphic lenses to achieve a super wide 2.76:1 aspect ratio, most famously used in the chariot race scene of Ben Hur.
Super Panavision 70 | 2.2:1 | 1959
While MGM 65 didn’t get extensive use, where its big impact comes from is its evolution by Panasonic into Super Panavision 70. Panasonic adapted the system to use spherical lenses instead of anamorphic ones, streamlining both the shooting and projecting processes. The resulting films followed Todd AO’s 2.2:1 aspect ratio. It was used for Lawrence of Arabia and, modernly, by Quintin Tarantino in The Hateful Eight.
IMAX | 1.43:1 | 1970
Much like VistaVision took the 35mm standard and turned it sideways to get a bigger frame, IMAX took the 70mm systems, rotated them to be vertical, and increased the amount seen above and below the typical view. The taller 1.43:1 is not far off of the original 4:3 aspect ratio, but because of the large film frames, it captures an enormous amount of detail. Like Cinerama, the huge screens and high quality has made IMAX a natural choice for documentary, nature and travel films, but it has also been used in a number of Hollywood films including The Dark Knight, Star Wars: The Force Awakens and Dunkirk.
HDTV | 16:9 (1.78:1) | 1996
As HDTVs were being developed, the question about what aspect ratio to use was a major decision. 16:9 was chosen because it was the median between the old 4:3 TV standard and the widespread 2.35:1 cinematic widescreen standard. By choosing 16:9, the least amount of footage can be lost when adapting either of those standards to fill the screen.
The vast majority of modern television programming is created in 16:9, and virtually all internet players, including Netflix, Hulu and YouTube, use it natively.
DCI 4K | 19:10 (1.9:1) | 2005
DCI 4K was defined in 2005, but hasn’t been seen much until recently as digital cameras and monitors had to catch up to the resolution. DCI 4K is the native resolution most commonly seen in digital cinema projectors (though higher resolution projectors have started to emerge), and many digital cinema cameras natively shoot in a 19:10 aspect ratio.
While a lot of digital tools are set up to natively run 19:10, it’s not as common since TV prefers 16:9 and films prefer 2.35:1.
Modern Web Aspect Ratios
With modern web presentations and smartphones, there is again a proliferation of unusual aspect ratios being used. Unlike the 1950’s when decisions were based around driving people to the cinema, these aspect ratios are being chosen by tech companies to fit common devices consumers have on hand.
While perhaps most commonly associated with Instagram, many social networks are adapting square (1:1) frames, and slightly vertical (4:5) aspect ratios are growing in popularity as well, allowing content creators to utilize more screen space on phones.
While these aspect ratios work great for their purposes, unless you are trying to evoke a very specific feeling, it’s not recommended to use them for television or film content as the amount of empty screen space becomes somewhat overwhelming. However, if you were creating content for a company to use for branding purposes and social media, versions in square or vertical aspect ratio are worth looking into.
When Should I Use an Aspect Ratio Calculator?
If you’re planning on presenting in an aspect ratio that doesn’t match your native capture, you need to figure out how to adapt your footage to your player. You can use an aspect ratio calculator to help you determine the resolution your final footage needs to be in by telling it the maximum number of pixels in one direction and the desired aspect ratio. The calculator will tell you the final dimensions you need.
Knowing these values, the dimensions of what it can be displayed on, and the resolution of your source footage, you can determine whether you need to crop or add letterboxes to create your final project.
Trying to decide on a film aspect ratio can initially be a daunting process. With digital processes, you can create video in any set of dimensions you want, giving you many aspect ratio options. However, by knowing the common aspect ratios (and how they have been used in the past), you can make an informed decision on how to achieve your artistic goals.
Post a comment