Depth of Field

I was always impressed by the effects of 'Depth of Field'. After I bought my camera, I tried to get the effect by stupidly increasing aperture, decreasing it randomly but none could create the effect. I wanted to achieve the shallow depth of field.

Even after reading many articles and watching videos on youtube I couldn't get it. After many experiments this is the first shallow depth of field, I could create.

How to achieve it:
1) Keep your subject at a distance (say 5ft)
2) Check the aperture, it should be as minimum as possible.
3) Zoom(say 10x) to the subject
4) Focus the subject (with center or spot)
5) take the picture

Here are some of the pictures with shallow depth of field(& focus) effect