Background out of focus:Influence of sensor size on depth-of-field

Sensors come in many different sizes and the size of the sensor has a direct relationship to light sensitivity. Large sensors perform better in low light, and a large sensor creates a more shallow depth of field to the image. The critical factors affecting depth of field is the aperture setting on the lens, the sensor size, and the chosen focal length.

For the cinematographer, understanding the sensor within a camera, is key to producing cinematic images.

It is worth mentioning that the small sensor tends to exhibit more noise than large sensors. Just like 16mm film was more grainy than 35mm motion picture film, a large sensor contains more information than a small sensor and this shows in the low light performance.



There are other considerations which will affect the look and quality, such as recording codec, resolution, and of course lens choice and the aperture you choose to shoot at.

Regardless, sensor size certainly has a major influence on depth of field and low light performance. It is therefore an important consideration when choosing the right camera for the job.



For those filming with smaller sensors it can be difficult, or impossible to suitably throw the background out of focus. This can make producing cinematic looking images difficult, and contributes to what many call the “video look.”

There is a solution to this problem.

Buy using a dedolight in combination with an image, one can project an image onto a background, and then throw the background out of focus. The result, when recorded, shows an out of focus background with the foreground subject in focus.



We can therefore simulate the large sensor look with a smaller sensor - this means we can produce cinematic images regardless of sensor size.

As cinematographers our job is to create the look and feel of a scene through all the tools available to us. The tools provided by dedolight, specifically focussing lights in combination with a dedo imager, enables us to project an image on a background, control the focus of the background image, and create truly cinematic results regardless of which camera you are using.



Text, image and video via Rick Young

NOTE: Other great solution and with a great price is the Light Blaster  a strobe-based image projector that I have used a few times with amazing results. More info www.light-blaster.com