Formats and Frame Rates — Sensor Size, Resolution and Delivery Specs, Codecs, RAW and LOG, Frame Rates, Slow Motion

A larger sensor makes shallow depth of field easier at the same angle of view, and lenses and cameras tend to get bigger too. A smaller sensor means lighter gear and deeper depth of field, which makes focus easier. Neither is simply better; it’s about matching the look of the project and the conditions on set.

Delivery follows the spec sheet set by whoever receives the film. It lists resolution, frame rate, codec, aspect ratio, color space, and audio and subtitle formats. Shooting at a higher resolution than delivery gives you room in post to crop slightly to refine framing or stabilize shake, but the data grows by the same amount.

• Codec — The method used to compress video. Codecs that compress groups of frames together make small files but are heavy to edit; codecs that compress each frame separately make big files but edit smoothly.
• Bitrate — The amount of data recorded per second (Mbps). Higher means more detail and bigger files.
• Bit depth — The number of tonal steps per color. 10-bit has far more steps than 8-bit, so smooth surfaces like the sky show less banding when you grade.
• RAW — Records sensor data almost as is. You can change white balance and ISO widely in post, but files are large and need a conversion step.
• LOG gamma — Squeezes brightness into a log curve to keep more highlight and shadow information. It looks gray and washed out as is, so you shoot while viewing through a LUT and finish the color in post.

Work out storage from the bitrate in advance. For example, shooting one hour at 400Mb (megabits) per second is 400 × 3,600 ÷ 8 = 180,000MB, about 180GB. Multiply by the day’s footage and the number of copies to get the card and drive capacity you need.

Within one project, set a single base frame rate and match every camera, the sound recording and timecode to it. Even 24 and 23.976, which look the same, drift apart in sound and picture when mixed. Follow the delivery spec and the standard set by the post team for which value to use.

Shoot faster than the base rate and play back at the base rate, and motion slows down. How many times slower is shooting fps ÷ playback fps.

• You need more light — Holding a 180-degree shutter at 120fps gives a 1/240 s exposure, about 2.3 stops darker than at 24fps (1/48 s).
• Flicker — The faster the shutter, the more light flicker shows. Do a test at those exact settings.
• Camera limits — Depending on the model, high speed may lower the resolution or use only part of the sensor, narrowing the angle of view.

If the sensor’s ratio differs from the delivery aspect ratio, shoot with a frame guide (mask) on the monitor. For example, delivering 2.39:1 from a 3840-wide image uses only about 1,607 pixels of height, so set your headroom knowing the top and bottom will be cut. For composition by aspect ratio, see the aspect ratio comparison in “Shot sizes, angles and composition.”