If HDR is enabled, when setAperturevalue is used it also forces setApertureNew to the following values: [value, value, value, 1].
Execute setApertureNew after setAperture to override this default mechanic.
Important
The aperture is set to default by the engine at the mission start. If you set it before the mission started it will reset like it never happened.
Make sure you set it at the right time (see Example 2).
The aperture value to simulate typical daylight (outdoor) conditions is 50. The aperture value to simulate typical daylight (indoor) conditions is 30.
Setting the value to less than 20 will result in a very bright scene, suitable for night conditions.
The closer the number is to 0, the more light will be let into the lens, to carry on the aperture metaphor.
Different lighting/weather conditions can change the actual indoor and outdoor aperture values. Experiment and test to be sure.