Shutter speed is the speed of your shutter. Hahahha. Shutter speed nie sebenarnya masa bukaan shutter korang. Ergh! Mcm ne nak sebut dlm English ek. Hmmm. Shutter speed is actually the length of time the camera's shutter open. Represent in seconds. Example: 2, 3, 1/10 or 1/20 seconds.
Remember this: the longer the shutter open, more light will able to enter the camera.
ISO is international standard of organization. Kita bukan nak buat quality management ke apa kat sini. Tapi ISO is actually a standard that we all use, before this known as ASA.
ISO ni sebenarnya tahap sensetif filem/sensor camera kita terhadap cahaya. Or in English, ISO in photography actually means the sensitivity of the film/sensor towards light. Example of representation, ISO 100, ISO 400 or ISO 3200.
the higher ISO u use, the noisier it becomes.
choose ISO based on your lighting(surrounding) if u've already in good lighting, use low ISO. if u're in low light area, use higher ISO.
Aperture nie sebenarnya lubang dlm camera korang yang membolehkan cahaya masuk. Or in English (cewah!!) Aperture is holes that allow lights to travel inside your camera. Examples of Aperture are represent like this, f/1.4, f/1.8, f/3.5 or f/11. Different apertures also result in different depth-of-field. Some called it bokeh/background blur/out of focus. the smaller the number of aperture, the more the out of focus area blurred.
Remember this: the smaller the number of aperture, more light will enter the camera (the bigger the hole opened).
Ok now let's talk about how they relate to each other.
To capture a moving subject, u will need faster shutter speed. Since faster shutter speed needed, less light enter the camera. There for, u'll need the smallest number of aperture to allow more light entered the camera. However, in certain condition u'll force to use higher aperture but don't worry, here were the ISO take their part. Use the higher ISO so that your film/sensor became more sensitive to light and enable u to use fast shutter speed with bigger number of aperture.
But always remember that higher ISO result in noisy picture. So try to avoid it if possible.
Fast shutter speed – because we don't want the picture blurred.
Smallest number of Aperture – to let more light enter the camera.
Higher ISO – to make film/sensor more sensitive.
To capture non-moving subject, normal shutter speed are required depends on capability of u holding the camera without shaking it. Since the shutter speed needed is slightly normal to slow, a smallest number of apertures are not a must. Unless u're taking picture with great depth-of-field(DOF) to get a fantastic blurred background(bokeh). In this condition we normally use ISO 100 to ISO 200.
But always remember, if the shutter speed were too slow, it may affect your picture become blur.
Slow shutter speed – because subject did not moving.
Aperture – depends. want bokeh, use smaller aperture.
Low ISO – avoid noises.
1/20 to 1/40 – human motions.
Here is a simulator to better see how they work with each other.