Full Frame – What is it?

by Milos Itic on March 11, 2011

In cinematography, full frame refers to the use of the full film gate at maximum width and height for 35 mm film cameras. It is sometimes also referred to as silent aperture, full gate, or a number of other similar word combinations. It is the original gate size pioneered by William Dickson and Thomas Edison in 1892 and first used in the short film Blacksmithing Scene. Full frame is generally used by all 4-perf films, whether silent, standard 35 (Academy ratio width), or Super 35. The introduction of Academy ratio in 1932 required that the lens mount needed to be shifted slightly horizontally to re-center the lens at the new center of frame; however, the gate size did not change as the extra negative information would be cropped out by lab processes in post-production. 4-perf Super 35 is nearly identical to the original full frame standard, although the lens mount requires vertical re-centering when common topline extraction is used. It should also be noted that hard mattes for all common ratios exist and either replace the film gate itself or are inserted within it. However, these are usually not used in the event that any reframing needs to be done.

Full-frame-what-is-itA full-frame digital SLR is a digital single-lens reflex camera (DSLR) fitted with an image sensor that is the same size as a 35 mm (36×24 mm) film frame. This is in contrast to cameras with smaller sensors, typically of a size equivalent to APS-C-size film, much smaller than a full 35 mm frame. As of 2007, the majority of digital cameras, both compact and SLR models, use a smaller-than-35 mm frame, as it is easier and cheaper to manufacture imaging sensors at a smaller size. Historically, the earliest digital SLR models, such as the Kodak DCS 100, also used a smaller sensor.

If the lens mounts are compatible, many lenses, including manual-focus models, designed for 35 mm cameras can be mounted on the latest DSLR cameras. When a lens designed for a full-frame camera, whether film or digital, is mounted on a DSLR with a smaller sensor size, only the center of the lens’s image circle is captured. The edges are cropped off, which is equivalent to zooming in on the center section of the imaging area. The ratio of the size of the full-frame 35 mm format to the size of the smaller format is known as the “crop factor” or “focal-length multiplier″, and is typically in the range 1.3–2.0 for non-full-frame digital SLRs.

 

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