For example, in the case of the C300 camera, such a video specification is as follows: With scene illumination of 2000 Lux at 3200 degrees Kelvin, a reference white of 89.9% reflectance, camera Master Gain set to 0 dB, Gamma and Detail enhancement switched off, the lens T-stop setting to produce 100 IRE of Luma video level on a waveform monitor is T-10, under which conditions the camera Lumasignal to noise ratio is 54dB. Imperatives of Digital Cinematography
The traditional broadcast video specification for lens-camera sensitivity is measured bythelens aperture setting in F-stop required to achieve 100 IRE units of Luma when the system is imaging a reference white chart having 89.9% reflectance under 2000 Lux of 3200 degree Kelvin illumination (with Camera Master Gain set to 0 dB, Gamma switched off, and all image enhancement switch off). Under those conditions, the amount of electronic noise in the image is another important issue closely allied with this sensitivity specification because of its bearing on dynamic range.
Shutter Control: Shutter timing on the EOS C300 can be set to any of the following methods: • Shutter Angle (range 360°~11.25°) • Shutter Speed (range 1⁄24 ~ 1⁄ 2000 second, at 23.98 fps; slow speed varies depending on fps) • Slow Shutter (range 1⁄3 ~ 1⁄30 sec.
At this ISO 800 setting the formal sensitivity specification of the EOS C700 camera – in traditional television terms is: With 2000 Lux of illumination a t 3200 degrees Kelvin, Camera set for 1920 x 1080 @ 29.97P , 1/30 second shutter speed
In traditional video terms the reference “anchor” is the 89.9% reflectance white chip (found on most gray scale charts) . With the camera operating at a specified frame rate, and Master Gain set to 0dB, the test chart is illuminated by 2000 Lux of 3200 degree Kelvin lighting , and the lens aperture is adjusted to produce the familiar 100% Luma video level on the waveform monitor ( equivalent to 700 mVolts peak in terms o f analog Luma signal ).
