Sensor Size and Filmmaking: Choosing the Right Camera for Your Project

In order to best execute your vision as a cinematographer, it's important to understand all of the technical factors that contribute to how your camera sees the world. There are many variables to consider before choosing the right camera for your project and in this article we'll discuss the most common types of sensor sizes available to filmmakers and how they may help or inhibit you as a visual storyteller.

A Brief History of How Full Frame Cameras Became Popular with Filmmakers

If you started your filmmaking career after the so-called "DSLR Revolution" there's a possibility that you may have adopted the idea that a "full frame" sensor is the standard sensor size for all digital cameras. While this may be largely true in the photography world, it's not the case in the filmmaking world – at least not yet! Super 35mm has been embraced as the standard film/sensor format for cinema cameras since the mid-1990's. By comparison, Super 35mm has an approximate 1.5x crop factor compared to full frame.

It wasn't until 2008 with the release of the Canon 5D Mark II that the technological language between photography and filmmaking started to mingle. The 5D Mark II had a full frame sensor, which is nearly equivalent in size to 35mm photography film. It also happened to be the first DSLR to have a full 1080p HD video feature, which was included by Canon to provide photojournalists with the ability to film their stories in addition to photographing them. A side effect was that filmmakers realized that this was a relatively cheap option for getting the previously-coveted and expensive "shallow depth of field" look due to the 5D's extremely large, full frame sensor. Prior to the DSLR revolution, it was very common for digital cameras used by indie and student filmmakers to have a ⅓ inch sensor or similar in size. For reference, a ⅓ inch sensor has a 6.9x crop factor compared to a full frame sensor. Shallow depth of field was out of the question for these cameras without the help of an expensive and cumbersome lens adapter. In addition to the hefty price tag, these depth of field adapters introduced problems such as light loss and significant image degradation in low light situations.

Cheap technology creates greater accessibility. Video-capable DSLRs and mirrorless cameras have sparked a filmmaking revolution by giving thousands of budding filmmakers access to a "cinematic" camera. Many successful cinematographers, such as Katelin Arizmendi and Ryan Booth, have gotten their start with the help of accessible large sensor cameras as a result of the DSLR revolution.

Today's Camera Sensor Options for Filmmakers

The popularity of the 5D Mark II with filmmakers has encouraged Canon and other companies like Sony, Nikon, and Panasonic to integrate video capabilities into their photography cameras. The most common sensor sizes among these cameras are as follows in descending sizes: full frame, APS-C, and Micro Four Thirds. Affordable digital cinema cameras eventually made their appearance into the market and a large majority of them have adopted the Super 35mm sized sensor, which happens to be very similar in size to APS-C. For a recap on how sensor size affects perceived field of view, please check out these resources:

New DSLR Owners: What You Must Know About Full Frame vs Crop Frame Sensors Before Choosing a Lens

Introduction to Full Frame vs Crop Frame Sensors Plus Great Sensor Comparison Resources

Aspect Ratios and Sensor Sizes for Video Beginners

Sensor Qualities to Consider for Filmmaking

Depth of FieldAs mentioned earlier, the introduction of the 5D Mark II brought an important cinematic tool to indie filmmakers: the "shallow depth of field" look. As a rule of thumb, the larger the sensor, the more shallow the depth of field can be. For example, the depth of field of an image shot with a lens set to f/2.8 on a full frame camera will be more shallow looking than an image shot with a Super 35mm sensor camera with the same lens that's also set to f/2.8. You can still easily achieve shallow depth of field when shooting with a Micro Four Thirds camera if you use fast lenses, such as Veydras and especially Voigtlanders. Learn more about depth of field and full frame sensors with the help of these resources:

The Bokeh Effect: How Sensor Size Affects Background Blur

How Crop Sensors Affect Depth of FieldIt's worth noting that the larger the sensor, the more difficult it will be to pull and maintain focus on a mobile subject, especially while shooting wide open on your lens. Pulling focus is a skill that can take an entirety of a career to master. It's even expected that professional Hollywood camera assistants with decades of experience to flub focus from time to time throughout a shoot. I say this just to give you an idea of how hard the art form can be.

Field of ViewFull frame sensor cameras provide a wider field of view in comparison to Super 35mm/APS-C sensor camera and even more so than Micro Four Thirds. It would be especially helpful to have a camera with a larger sensor if you'll be shooting in a cramped area and you want to show more of the location. Having the wider field of view of a full frame sensor lets you achieve wider shots than what you would get with the same focal length on a camera with a smaller sensor. This allows you to get closer to your subject with a larger sensor camera and a longer lens without having to worry about the barrel distortion that can be present with wider lenses.

Rolling ShutterA shutter is a device that prevents the sensor or film from being further exposed to light and is activated after a duration of time based on the camera operator's exposure settings. Cinema film cameras have a physical rotary disc with an opening, which allows light to pass through to the film. The sensors on digital photo cameras and digital cinema cameras are electronically controlled. Pixels on the sensor are scanned in rapid succession, then the process is reset and repeats for the next exposure.

Rolling shutter refers to a method of scanning which involves pixels being scanned row by row from left to right until the entire sensor has been scanned and completes the exposure. The exposure terminates in the same manner, with the pixels on the sensor shutting off row by row, from left to right. DSLRs, mirrorless cameras, and most digital cinema cameras use a rolling shutter. It's important to note that while DSLRs also have a mechanical shutter, it is recessed when the camera is set to video mode, continuously exposing the sensor.

Digital cameras that use a rolling shutter can suffer from a "jello effect", which is the bending or wobbling of an image when the camera or subject is moving too quickly for the rolling shutter to keep up.

Filmed at 28mm f/4 in APS-C mode:

View post on imgur.com

Filmed at 45mm f/4 in full frame mode:

View post on imgur.com

The larger the sensor, the worse the jello effect can be due to the larger surface area that needs to be scanned. If you plan on filming fast action sequences or making fast camera movements, you may want to consider using a camera with a smaller sensor or use a camera with a global sensor. Global sensors scan all of the pixels of the entire sensor at the same time as opposed to row by row, which would eliminate the potential of the jello effect. The Blackmagic Production Camera, Blackmagic Ursa Mini 4K (but not the 4.6K), and the AJA CION are among the few cameras that use a global shutter.

Beautiful and important work has been filmed with large and small sensor/film format sizes. There are many important features of a camera to consider aside from just sensor size and, when it comes down to it, a camera is just a tool and it's a matter of choosing the right tool for you!

The following two tabs change content below. Mike Sun is a Video VIP Quality Control Technician Lead at BorrowLenses and a freelance cinematographer and photographer.
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