The physical dimensions of a full-frame sensor date back to the early 1900s when 35mm film emerged as a universal standard for filmmaking and, later,as 135 film for stills photography. In traditional movie-making, film travels vertically through the camera, providing a variety of different image formats.
One of them, 3 Perf, uses just 3 perforations in the film per frame equating to an individual widescreen frame of 24.89mm x 14m, commonly referred to as Super 35mm. For stills photography, film travels horizontally through the camera providing the largest of all the popular image formats for 35mm film, with a 36mm by 24mm frame, using 8 perforations on the film for each frame, traditionally called Full-Frame.
At the turn of the 21st century, digital cameras with Super35 size sensors (including Sony’s revolutionary F35) proved good enough to challenge film cameras and started the digital revolution in Hollywood and across the world. For the next generation of filmmaking cameras, however, manufacturers began to think bigger than Super 35. A lot bigger.
Full-Frame copies the frame size from 35mm film stills cameras, allowing the same lenses and lens mounts from older film cameras to be used in new digital stills cameras, with the same look and feel, principles of photography, framing, focus and depth of field. It also allows for backwards compatibility with Super 35 and other formats.
Since a full-frame sensor is bigger than a Super 35mm sensor, it naturally captures a wider image. Shooting from the same position with the same lens, a full-frame camera allows you to see more of the scene which can be helpful in certain situations. The below images help illustrate this.
Full-frame sensors offer the opportunity of narrow depth of field by maximising the creative possibilities of large aperture lenses. By using both a lens with a large maximum aperture, and a full-frame sensor, it is easy to achieve a very narrow depth of field in the image. A narrow depth of field means particular objects in the scene can be picked out, pushing everything in front and behind out of focus. Audiences can be subliminally directed to look at certain objects in the scene as part of the screen play or story-telling process.
Shallow depth of field
Wide depth of field
The size of a full-frame sensor allows a camera to support many more formats. By selecting and recording regions of the sensor it is possible to extract a variety of high-quality images to suit different shooting requirements, and formats. For instance, VENICE’s switchable imager modes can support an unprecedented number of cinematic aspect ratios for complete creative freedom.
Since a Full-Frame sensor is bigger, this can mean higher resolution (with more photosites) or increased sensitivity (with larger photosites) or as is usually the case: a careful mix of both. High resolution can also be used for oversampling where the sensor captures more pixels than required in the final image, but uses advanced image processing in the camera to boost clarity and retain fine detail that might otherwise be lost with a smaller sensor with less resolution.
Photosites for various sensors with similar resolutions
In addition to all the inherent benefits of full-frame sensors, there are additional technologies that can further enhance real world performance and creative flexibility.
Dynamic range is normally measured in stops, a measure of the aperture or iris in the lens. A better sensor is able to differentiate more stop levels of grey between black and white. For instance, the human eye has a dynamic range of about 10-15 stops.
Full-Frame sensors can provide enhanced dynamic range with a relaxed design space and larger photosites. Sony’s Exmor R sensor, adopted by FX9 extends this benefit by radically realigning the pixel structure as shown below. Consequently, Sony Full-Frame sensors can achieve dynamic ranges equal to, or even exceeding what the human eye can capture.
Conventional front-illuminated sensor as used in FS7II
Digital imaging sensors perform best when set to their base ISO. It’s at this base ISO value you will realise a very clean image with low noise, your best signal to noise ratio, and most likely the widest dynamic range. This is because at the base ISO setting, there is no amplification, or gain (voltage), being added to the signal coming from the sensor. Adding gain, or increasing ISO, to make an image appear brighter also adds noise. Increase the gain to make an image appear twice as bright and you’re also introducing twice as much noise to the signal and image quality is thusly decreased. While grain on analog film, like at ASA 400 for example, might be pleasing and enhance the feel of an image, the introduction of digital noise to an image rarely brings a similarly pleasing result.
Therefore, the VENICE and FX9 camera’s full frame sensor has what is termed Dual Base ISO. Dual Base ISO means the camera’s imaging sensor has two distinct sensitivities to light.
VENICE has a base ISO of 500 to provide the optimal dynamic range for applications where on-set lighting is standard. A secondary High Base ISO of 2500 excels in low-light High Dynamic Range capture. FX9 features a base sensitivity of ISO 800, providing the optimal dynamic range for applications such as shooting outside or in brightly lit interiors. A secondary High Base sensitivity of ISO 4000 excels in low light scenarios.
FX9 is the world’s first full-frame camcorder with an electronic ND (neutral density) filter which, at its simplest, removes the need for manually fitting and changing fixed filters. This is no small benefit, but by combining a Full-Frame with a large aperture auto-iris lens, and an electronic ND filter, it is possible to create scenes that change in ways never seen before. Alter the ND filter during the shot and the iris will automatically adjust to maintain good exposure, thus changing the depth of field as the scene progresses. If the lens is not an auto-iris type, no problem! Simply switch the electronic ND filter to auto, and adjust the iris during the shot to create the same effect. Take a look at the Electronic ND Filter Tech Guide for more information on how to use the electronic ND filter.
The shallow depth of field which is so distinctive for full-frame cameras also creates a challenge for the camera operator in maintaining such a precise focus. For a high-end cinematography camera like VENICE, it’s traditional for a focus puller to manually maintain this focus. In other, non-scripted applications like documentaries or news, this isn’t practical.
Camera operators traditionally look down upon autofocus systems as insufficiently accurate and restrictive of their creative flexibility. However, with FX9, Sony implemented an advanced autofocus system never before seen on a full-frame professional camcorder. Its precision allows for exceptionally shallow depth of field, while also supporting a wide range of creative options in terms of speed and tracking. So rather than restricting an operator’s creative options, it provides a tool for additional creativity and makes full-frame’s shallow depth of field practical for almost any given scenario, from slow-moving period drama through to high-speed sports.
The VENICE camera is Sony’s first full-frame sensor high-end digital cinematography camera. It is unmatched in the Sony range for the wide array of recording formats it supports and features Dual Base ISO 500 / ISO 2500.
The FX9 features a full-frame 6K sensor with high quality recording in DCI 4K*, Ultra HD and HD resolutions. Powerful image processing with debayering and oversampling ensures image quality beyond the limits of conventional Super 35mm sensors. It is the world’s first full-frame camcorder with electronic variable ND, high Fast Hybrid AF and has Dual Base ISO 800 / ISO 4000.
*Future update is required.