Journey by Lijo Jose

You might have seen some photos with background blurred. sometimes foreground blurred. Blurring in photos is like silence in a talk. Some amount of blurring make the photo more beautiful. In photographic terms it can be interpreted by Depth of Field(DoF).

Depth of field refers to the depth of focus area in the photo. or the area of depth which is sharp. Shallow depth of field means the the depth of focus is narrow. Shallow DoF makes the background more blurred and this kind of blurring is referred as Bokeh (More about bokeh at http://en.wikipedia.org/wiki/Bokeh).

Three things matters in DoF adjustments.

1. Amount of zoom
In Point and Shoot camera(normal cameras) with low zoom(1x), you can observe wide DoF. As zoom increases(say 12x or so), the DoF will be narrow(shallow).

at 18mm . An example of wide DoF

In DSLRs, zoom is explained using the focal length. with small focal length, you can cover more area. As focal length increases, the area reduces. Lenses are available from focal length 10mm ranging to 1200mm.

    At low focal length(say 18mm), the DoF will be wide.

Use 300 mm, you can see shallow DoF

at 300mm . An example of shallow DoF

2. Use of aperture
Once i have gone through the site and found a nice introduction about aperture. Really informative. Coming to DoF, with low aperture say f/2.8, you will get shallow DoF.

 With high aperture, you can get long DoF. Most of the point and shoot cameras will have aperture from f/2.8 to f/8.

3. distance between the object in focus and the surroundings with respect to camera
With the above points, you can experiment with the distance between point of attraction and the background/foreground.

As a final tip, you can escape from surrounding distractions by using shallow depth of field. i.e. by blurring the background.