The sensor is paired with the Canon DiGIC DV7 image processor, which uses the sensor's raw information and processes it for various applications such as high frame rate recording, raw recording, HDR-PQ output, electronic image stabilization (EIS), and proxy recording. The camera records up to DCI 4K resolution video to dual CFexpress cards, and an SD card slot is available to record additional images. High frame rates up to 120 fps can be recorded in 4K raw, and up to 180 fps in 2K cropped mode. Canon's Cinema RAW Light and XF-AVC recording formats are supported, providing DCI 4K images with a 10-bit, 4:2:2 Long GOP codec. Proxy recording is also supported, which allows a significant boost to your post-production speed.

For more flexibility during post-production, the camera also offers Canon's Log 2 and Log 3 gamma modes, which results in excellent tonal reproduction in the highlight and low-light regions of an image, and an expanded dynamic range. The C300 Mark III also supports custom user LUTs that can be utilized on monitors, the LCD, or viewfinder to ensure the most accurate color. Canon's Dual Pixel CMOS AF (autofocus) support allows you to not only provide accurate autofocus, but it also features touch AF and face detection.

The camera features up to 12G-SDI output over a single BNC cable, timecode I/O, and genlock input BNCs. It supports up to 4-channel audio using the internal mic, mini-mic input, and XLR ports, and an expansion unit can be added to support up to four XLR inputs. The body has a modular design that can either be stripped down completely or be built up using the included handle, 4.3" rotating touchscreen LCD unit with full controls, grip, and thumb rest.