ABA Creation

the light enters and vice versa. If you want to see how it works just stand in the front of the mirror with a torch in your hand, light the torch direct in your eyes, now slowly get the torch off your eyes and towards your eyes. What happens? The pupil of your eye shrinks small to control the amount of light enters into your eye, when you get torchlight directly into your eyes and when you remove torch off your eyes the pupil shrink large to allow more light to enter. The same thing happens with your camera and when you use manual mode you control this yourself.

Actually, the question is how you want it to? everything depends on the type of photograph you want to capture. If you are photographing landscapes(pic-1), you need to set larger f-stop number(smaller aperture opening) and while taking closeups you may need to set smaller f-stop number(larger aperture opening). This is called depth of field(we'll discuss this topic in our later post). If you want your subject to be in focus and everything out of focus(pic-2), then you must set smaller f-stop number(larger aperture opening), and if you want to make everything in focus then set larger f-stop number(smaller aperture opening).

Pic-1 Shutter 1/125,APERTURE f/11 ISO-100

In pic-1 I need short depth of field and want everything the background and foreground in focus, so I set the aperture f/11, actually when taking a landscape photo, it good to be above f/11, though f/11 worked for me here. You can set the aperture at f/14 and above.

Pic-2   Shutter 1/250,APERTURE f/5.6 ISO-100

In Pic-2 you can see the foreground and background are out of focus and extra depth of field is used.You can achieve this result with smaller f-stop number (larger aperture opening). I use f/5.6 but don't hesitate to go with more smaller f-stop number(larger aperture),f/1.4 or f/2.8 can also create magic.
There is no hard and fast rule, just believe in yourself and do what suits you. All will comes with practice, the best way to learn anything.