Aperture, shutter speed, exposure, yada yada yada. Does it all sound German?? If you answered yes, that is okay! Here is an easy analogy that will make all those confusing words a bit more understandable.
Think of your garden water hose that you are using to fill a bucket with water.
- The diameter of the hose can be thought of as the aperture: the larger the diameter, the more water flows through.
- The length of time you leave the tap open can be thought of as the shutter speed: the longer you leave the tap open, the more water flows through.
- The speed of water flow can be thought of as the ISO: the faster the water flows through the hose, the more water flows through.
- The amount of water that collects into the bucket is the exposure.
Let's also pretend that you have two water hoses.
One with a small diameter (F8 aperture)
The second with a larger diameter (F2.8 aperture)

To fill our bucket, we experiment with the
smaller of the two hoses and find that we need to leave the tap open for 10 min (our shutter speed of 1/30 sec.).
So, here we have the following 'exposure setting':
- Small hose & long time of 10 min.
- small aperture (F8) & slow shutter speed of 1/30 sec.
OK, so what happens if you use the same small hose but close the tap after, let's say, 3 min? Of course, it's clear that the bucket won't be full.
That is exactly what you did when you kept the same aperture and used a faster shutter speed. Not enough light came in to properly expose the image sensor ('the bucket is not full'). What do you have to do to fill up the bucket? Use the bigger hose! Aha, now with more water gushing out of your bigger hose, you can now close the tap earlier and still obtain a full bucket.
Similarly, to use a faster shutter speed, you need to use a larger aperture. Dial in F2.8 at 1/250 sec. and presto! you've just taken a perfectly exposed picture
Here is your new 'exposure setting':