Tutorial: Exposure

After photographing for about 4 years, I have learnt many, many things. From the time I was using Auto Mode, switching into different modes (portrait, night, etc), then gradually changing to the semi-manual then the fully manual modes. So because I'm such a "nice person", I decided to share my knowledge for newbies or people who just need to remind themselves about their basics.

So let's just start with the easiest of all, exposure or shutter speed.
What is exposure?
Exposure is basically the term used for the amount of time the shutter is open for the light to hit the sensor. So the longer you leave it open for, the more light it receives.

How is it measured?
It is measured in seconds or fractions of seconds. The bigger the number, the longer it is open. So logically speaking 1sec is longer than 1/50sec.
Every shutter speed has their purpose to it. There is no right or wrong in choosing it, as it just depends on what shot you plan to make.
Even though there is not much rules to this key aspect, there are a few rules that you should keep in mind.
For any shutter speed lower than 1/50sec (e.g. 1/6, 1/3 etc...) you should use a tripod or some kind of support to avoid camera shake. Even if you don't have a tripod or anything cameras are coming out with built-in image stabilisation which helps stop camera shake up to a few stops down.

How can I effectively use it?
Well, here's a question you should ask yourself. Do you want to freeze movement? Do you want to show motion?
Freeze movement: For this option, you will want to use anything faster than 1/750sec. This also depends on how fast the subject is moving. So have a judge before you do anything.
Show motion: Anything under 1/200. Even though 1/200 is quite quick of a shutter speed, the subject can be blurred depending on how fast it is travelling. So again, judge on what your subject is, and how fast it is travelling.

At the speed of 1/250 of a second, you could see some blur, but you can still see the shape of the cylinder. But at the speed pf 1/6 of a second, all you can see is blur, and obviously after that, it just get's blurrier.