As professional camcorder sales become more and more dominated by large sensor cameras designed to emulate the aesthetically pleasing shallow DoF (depth of field) normally associated with 35mm film, we’ve learned that Sony have recently licensed and implemented a revolutionary new technology called VariDoF.
The acronym stands for Variable Depth of Field and through the combination of a super high resolution 65mm CMOS sensor, sophisticated secondary optics and a custom-manufactured RISC processing engine the system is able to seamlessly vary the effective sensor area, and therefore Depth of Field in real-time without the need to change lens or aperture…
Here is a schematic illustration of how the VariDoF system works:
This means that just as a DoP can today pull-focus or aperture, with a VariDoF camera it is now possible to ‘pull DoF‘ too, thus opening up a whole new dimension of creative possibilities.
The prototype camera looks like a PMW-350, however it is distinguished by a slightly elongated sensor block housing and VariDoF control port.The effective sensor size can be accessed and preset through the camera’s internal menu system. Preset sizes are 1/3″, 1/2″, 2/3″, s16, s35 and 65mm. A VDC-R1 remote controller can be connected to the VariDoF port to provide a precise control surface for real-time DoF control.
To vary the DoF the secondary lens system adjusts the lens’ area of projection whilst the active area of the CMOS sensor is simultaneously varied to match. Focus is tracked simultaneously so that the operator’s preset focus point is maintained.
Click HERE to view a demonstration of ‘Pulling DoF’
Here are some frame-grabs from the video:
The prototype camera featured a Sony 2/3″ B4 type lens mount, meaning that the camera could natively accommodate a wide range of ENG, EFP and Cine-Style lenses. Sony tell us that their adaptation of the VariDoF technology incorporates an inter-changeable lens mount system so that it can accept any lens from 1/3″ to PL mount with the secondary lens system compensating automatically for the different projected image sizes (via a menu setting).
Sony haven’t specified the resolution of their 65mm CMOS sensor, however they have confirmed that it can deliver a native 2K resolution in 1/3″ mode and would be able to resolve over 16K in 65mm mode if the recording medium and processing engine could handle it.
The VariDoF technology is the property of VariDoF Corporation Inc. and has not been licensed to Sony exclusively, therefore expect to see a whole host of other manufacturers ‘jumping on the bandwagon’ to deliver VariDoF cameras in the near future (If they’re not doing so already.
For further information see the VariDoF.com website or visit the NAB Show in Las Vegas later this month.