Anamorphic lenses distort the image, squeezing it horizontally while leaving the vertical aspect unaffected.
Anamorphic lenses distort the image, squeezing it horizontally while leaving the vertical aspect unaffected. Bolex Anamorphot Collection by Yan Kezyr is licensed under CC BY 2.0

There are two kinds of lenses that can be used in film making: spherical lenses and anamorphic lenses. Spherical lenses are the type that we all use most commonly and they pass the image to the sensor or film without affecting the aspect ratio. However anamorphic lenses distort the image, squeezing it horizontally while leaving the vertical aspect unaffected. To understand why filmmakers would want a lens to do this needs a little history lesson.

The birth of widescreen

Although a number of widescreen formats had been experimented with during the early days of cinema, the vast majority of films were shot in the standard 35mm “Academy” aspect ratio of 1.37:1 until the early 1950s. It was then that, to counter the decline in cinema audiences caused by the rise in popularity of television, film studios moved to making films in widescreen aspect ratios.

Some of the techniques used to achieve a wider aspect ratio simply involved masking the top and bottom of the 35mm film frame. However a cropped image produced in this way wastes a large proportion of each frame’s area, reducing resolution and increasing grain when it is projected.

Anamorphic lenses were developed to utilize the entire 35mm film frame, compressing the image horizontally by a factor of 2, while using the full height of the frame. When the finished film was screened at a cinema, the projector lens correspondingly unsqueezed the image back to its correct proportions. In this way, the classic 2.39:1 widescreen film aspect ratio could be obtained from film frames with an aspect ratio of 1.37:1.

The anamorphic look

While anamorphic lenses were developed to overcome the limitations of the 35mm film frame, they added a distinctive look to the images.

One of the most unique features of anamorphic images is that out of focus elements in the background produce a distinctive vertical oval bokeh. Lens flares are also visible as horizontal or vertical streaks across the frame.

Oval bokeh and lens flares visible as horizontal or vertical streaks across the frame are unique features of anamorphic images.
Oval bokeh and lens flares visible as horizontal or vertical streaks across the frame are unique features of anamorphic images. Bolex Anamorphot Collection by Yan Kezyr is licensed under CC BY 2.0

In use, anamorphic lenses have an effective shallower depth of field when compared to spherical lenses, which is often considered more cinematic. To understand this effect, consider that when you are using a 50mm anamorphic lens, it has the vertical perspective of a 50mm spherical lens but, because of the compression of the image along the horizontal axis of the image, the effective horizontal focal length is that of a 25mm lens. Therefore, to achieve a similar field of vision to a 50mm spherical lens a 100mm anamorphic lens must be used with the resulting shallower depth of field.

Anamorphic lenses and digital sensors

With the advent of digital sensors, the need to use anamorphic lenses diminished. Digital video sensors typically have a wider aspect ratio than 35mm film, and so spherical lenses can be used to achieve a widescreen image with only a minimal amount of cropping.

Using a standard anamorphic lens with a 2x compression factor on a digital sensor with an aspect ratio of 16:9 will result in a final image with an overly-wide 3.55:1 aspect ratio. To achieve a 2.39:1 aspect ratio, only the central portion of the sensor is used, which can mean that the final image uses fewer pixels than would be achieved by simply masking off the top and bottom of a full width sensor. Because of this, Arri released a version of their Alexa cinema camera with a 4:3 image sensor designed specifically to produce a 2.39:1 image when paired with a 2x anamorphic lens.

There are also a number of anamorphic add-on lenses with horizontal compression ratios of 1.33:1 or 1.35:1, which are designed to work in conjunction with spherical lenses on cameras such as DSLRs with 16:9 digital sensors. However, the lower compression factor means that these adaptors produce less of the characteristic anamorphic bokeh and lens flares that filmmakers seek.

Working with anamorphic lenses

While there are anamorphic lenses or add-on lenses which can be adapted to work with most cameras, there are a number of issues to consider before planning your first anamorphic widescreen project.

Unless your camera has an option to desqueeze the image in the viewfinder or on the monitor screen, you will have to work with the horizontally compressed image, making framing and shot composition more of a challenge.

Anamorphic lenses tend to be larger and heavier than spherical lenses, which makes them less suitable for run and gun filmmaking

Anamorphic lenses tend to be larger and heavier than spherical lenses, which makes them less suitable for run and gun filmmaking. They are also likely to have slower maximum apertures, so you will need more light when filming.

Wide angle anamorphic lenses can have more distortion than spherical lenses, making it difficult to get straight verticals in your image. The lens distortion produced by anamorphic lenses can also make working with visual effects more difficult.

The extra glass elements in anamorphic lenses can affect image sharpness, though some filmmakers actively prefer the softer nature of the glass when working with 4K or higher resolution digital formats as it can reduce the overly clinical nature of the footage.

Is shooting anamorphic right for you?

Anamorphic lenses are not suitable for everyday filmmaking. However, for the right project anamorphic lenses can increase your production values and give your film a uniquely cinematic look.

Pete Tomkies is a freelance cinematographer and camera operator from Manchester, UK. He also produces and directs short films as Duck66 Films.

Pete Tomkies
Pete Tomkies is a freelance cinematographer and camera operator from Manchester, UK. He also produces and directs short films as Duck66 Films.Pete's latest short Once Bitten... won 15 awards and was selected for 105 film festivals around the world.

3 COMMENTS

  1. I have often asked independent filmmakers why they shoot their films in anamorphic when the majority of their viewers will see their work on a television. There answer is because they like it.
    The next time you visit your local theatre notice that a 2.35.1 anamorphic release is no wider then the 1.85:1 film. The only difference is the shape of the frame and less height. In other words its a smaller image in the theatre just as it is on a TV.
    I was part of the wide-screen era as I experienced the thrill of seeing THE ROBE in CinemaScope with stereophonic sound. I watched as CinemaScope lenses gave way to the greatly improved images of Panavision. In those days the 2.35:1 or 2.55:1 as they were in the first few years were actually shown on screens that were wider. A 1.85:1 (such as most VistaVision films) had the same screen height but were not as wide. With todays Digital projectioning 2.35:1 OR 1.85:1 project at the same width. The theatre screenings are the same as they are on the TV.
    So I have a hard time understanding why a film maker whose work is mostly going to be seen on a television (or a phone) would chose to shoot anamorphic. I’d be interested in hearing from filmmakers.

    • Thanks for taking the time to comment and share your experience 🙂

      In the UK there are cinemas where the images are projected full height in both 1.85:1 and 2.39/4:1 with the screen widening for the wider aspect ratio and the 18.5:1 films do not fill the full width of the auditorium. However not all films released in 2.39:1 were shot with anamorphic lenses – some are shot with spherical lenses on a 16:9 sensor and then matted to the wider format.

      And just to confuse things further it is possible to render out a digital video file in any aspect ratio you like for projection. My last film was shot on a 16:9 sensor and letterboxed to 2.39:1 for viewing on TV via Blu ray etc. However when I prepared a Digital Cinema Package (DCP) file for screening at a cinema as part of a film festival I outputted a file in a 2.39:1 format [2048×858 as opposed to 1920×1080 of HD televisons].

      As to why people love to shoot anamorphic? There is a certain unique quality to an anamorphic image that film makers often yearn for as well as the distinctive oval bokeh and anamorphic lens flares.

  2. When I was a young boy I spent a lot of time thumbing through the family encyclopedia(Americana). One day I happened upon an article on CinemaScope. It featured a compressed photo taken from “the Robe”. I was fascinated. Movies in general fascinated me but CinemaScope beat them all. When my dad bought a silent 8mm film camera I was in heaven. After shooting 8mm film then in crappy Video I finally got a mirror less GH1 in which I installed the hacks and finally was able to capture cinema like images. Two years ago I discovered that I could buy old anamorphic projection lenses and shoot wide screen. I’m not a filmmaker but I love the cinema look. I took want my films to look professional. It drives me up the wall when people shoot vertical video. Where are their heads?

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