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. We’ll discuss common sensor sizes for filmmakers and how they affect 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” it’s possibile that you adopted the idea that a “full frame” sensor is the standard sensor size for all digital cameras. This is largely true in the photography world. But 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. To video folks, Super 35mm is thought of as “full frame” but it has an approximate 1.5x crop factor compared to still photography’s “full frame”.

It wasn’t until 2008 with the release of the Canon 5D Mark II that the 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. Canon included video so that photojournalists could 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.

Sensor Sizes

Prior to the DSLR revolution, indie and student filmmakers often used digital cameras with a ⅓ inch sensor or similar. 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 an expensive adapter. In addition to the price tag, these depth of field adapters introduced problems such as light loss and significant image degradation in low light.

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 these large sensor cameras.

Today’s Camera Sensor Options for Filmmakers

The popularity of the 5D Mark II with filmmakers got Canon and other companies to integrate video 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 way into the market. A large majority of them have adopted the Super 35mm-sized sensor, which happens to be very similar 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

Here are a few sensor qualities you must consider when choosing a camera.

Depth of Field

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 appear. 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 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:

• The Bokeh Effect: How Sensor Size Affects Background Blur
• How Crop Sensors Affect Depth of Field

However, the larger the sensor, the more difficult it will be to pull and maintain focus on a mobile subject. This is especially true when shooting wide open on your lens. Pulling focus is a skill that can take a whole career to master. It’s  expected that even professional Hollywood camera assistants with decades of experience will sometimes flub focus. I say this just to give you an idea of how hard the art form can be.

Follow Focus Like a Pro: Intro to Follow Focus Units for New Filmmakers

Field of View

Full frame sensor cameras provide a wider field of view compared to Super 35mm/APS-C/Micro Four Thirds cameras. It’s helpful to have a camera with a larger sensor if you’re 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 barrel distortion, which can be seen in wider lenses.

Rolling Shutter

A shutter stops light exposure on the sensor. It activates after a set time based on the camera operator’s exposure settings (shutter speed). 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 resets and repeats for the next exposure.

Rolling shutter is when pixels are scanned row-by-row from left-to-right until the entire sensor is scanned a scene exposed. The exposure terminates in the same manner, with the pixels on the sensor shutting off row by row, from left to right. This speeds up processing. Most digital cinema cameras use a rolling shutter. While DSLRs also have a mechanical shutter, it is recessed when the camera is set to video mode.

Rolling Shutter Visual Example

Digital cameras that use a rolling shutter can suffer from a “jello effect”. This bending/wobbling happens 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. This is 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 sensor at the same time as opposed to row by row. This helps get rid 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 more features of a camera to consider. A camera is just a tool and it’s a matter of choosing the right tool for you!