What is P-Iris and what does it do?

A P-iris is a type of auto iris, that offers automatic adjustment of the cameras iris opening and also precise control over all aspects of image quality.

Rather than being limited to a narrow focus on light levels as the sole determinant of an iris opening size, a P-iris works in co-ordination with software embedded into the camera to automatically determine and set the iris opening size that will produce the best picture quality. P-iris uses a sophisticated stepping motor to adjust the position of the iris with extreme precision.

A P-iris also takes advantage of electronic manipulation of parameters such as gain (amplification of signal intensity) and exposure time to achieve this extra level of optimization, while avoiding picture quality degradation due to optical phenomena such as diffraction that occur at boundary conditions when the iris size becomes very small. In a very bright environment, a camera with a P-iris is programmed to halt the contraction of the iris opening before diffraction effects are induced. So, while an ordinary auto iris would result in blurred images in this situation, a camera equipped with a P-iris avoids this side effect of diffraction while using other means to correct for the additional light that passes through the lens because the iris opening is not contracted to the same extent.



In simple terms – Whilst conventional DC lenses open and close the Iris based on light levels with no regards to how this will affect the depth of field of the image, P Iris lenses work in cooperation with the camera software considering light levels whilst optimising the depth of field.





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