The minimum illumination of Sony security cameras is measured at normal shutter speed (1/60 sec.).
Many security cameras can capture images at various shutter speeds ranging from 2 seconds to 1/10,000 second.1 When capturing images at normal shutter speeds (ex. 1/60 sec.), moving objects can be captured clearly without picture blur (see Vid. 1). On the contrary, when capturing images at slow shutter speeds (ex. 1 sec.), the camera’s CCD accumulates more light so that the image captured is brighter; however, for moving objects, the accumulation period can be too long, resulting in picture blur (see Vid. 2).
By using a slow shutter speed, it is possible to skew the minimum illumination value in a specification so that the lux rating is much lower than that taken at a normal shutter speed. However, because the resulting image is blurred, it is not useful in most surveillance monitoring applications.
1.The range of shutter speeds varies depending on the camera.
(Camera A has a 0.4 lux specification at 50IRE)
(Camera B can have a specification of less than 0.01 lux at 50IRE by using slow shutter)