The effect of speed used to capture moving images in movement without being blurry, or as in that case, so they are smooth or difuminated. These effects can be achieved by increasing or decreasing speed. Applying a rate of a 60 velocity we can capture the image without it being blurred, but if we instead apply a velocity rate of 5 or 10 the image will be blurred or faded.
To ensure that the water remains clear, we must adjust the speed at least 300. And so that water does not get to be blurred.
To ensure that water remains blurred we must adjust the speed to a maximum of 60. And get that water to be blurred.
The effect of sensitivity is used to use it when you make your photo still (no movement) in a night scene and that is illuminated only the essential part of the picture. It is often used in high sensitivity photos of fireworks.
When it is night time and you want your picture not too dark without using flash, or simply that the picture is good and not blur, sensitivity must raise at least to 400.
The function of the diafragma aperture serves mainly to make your photos look more or less bright, for example if you find a bright scenary you will have to open up the aperture for the picture is not so white. However if you come across a stage with very little light will be closed to the maximum to get more light.
Photos with the diaphragm very close for lack of light
Photos with the aperture wide open because there is too much light
This in effect serves depending on the picture you want. Or blurring the background, or if you prefer to keep the main person or object and background sharp too.