"How to blur the background in a photograph?" - Almost every beginner Photographer searches/asks this. || Depth of Field

There are various softwares that help achieving blur in photographs but here we are going to talk about Camera settings, which give a unique blur (bokeh).

When I started playing with camera, the very first thing I wanted to do was - click various subjects having blurred background. I have been doing various things and at times got very good results, but didn't know why I am able to blur the background but not every time. And the amount of blur was always varying.  Then I took the camera to my colleague in office and asked few basic tips. Tried few of them and then felt the need to reading more about camera settings & practicing them more. Here I am trying to share few basic tips about achieving blurred background in your photographs and have control on the blurriness. 

So in Photography, there is a term called 'Depth of Field' which is decided on the basis of camera settings and hence impacts the amount of blurriness we get in a particular photograph. Let's talk more about it.

What is Depth of Field? - Depth of Field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image. The image below would give some sense about it (picked from wikipedia.)

Don't worry, even if it's not very clear at this point of time.

So let's come to the point and talk about the ways to achieve max blur in your photograph -

1. Depth Of Field is related to Aperture( f value) in your camera. Lower the f value (higher the aperture), more blur you see in the background. So if you have lens with least f value as 3.5, you should use it and try to see the blur you get. Compare it with f8, f20. You will clearly understand what I am trying to say here. 

2. Lesser the distance between your camera and subject, shallower is Depth of Field. Which means that distance between your camera and subject also plays a big role in amount of blurriness you get, apart from Aperture settings.

3. Lens zoom also impacts the amount of depth of field you get. Blur effect increases if you shoot same subject without changing the position of camera and f value, but zoom-in. 

4. Distance between subject and background is also very important. More the distance subject and the background, more blur-effect you get.  

Exercise - Here is an exercise that will bring clarity about the concept of Depth of Field and Blurriness. 

a. Put a subject on a table and put your camera at a distance. Click photographs min f value and max f value, along with few more shots with intermediate f values. (f1.8, f8, f11, f22). Now compare the blurriness you get the background.

b. Now when you are done with first exercise, put your lens on min  f value on your lens and click few shots by moving you camera. Take the camera closer to your subject in 3 steps and take it away as well. Compare these shots.

c. Now fix f value, don't change position of camera & subject. Put something in the background and keep changing the distance of this background elements and main subject. Click 6 shots at different distance and notice the change.

Now things should be very clear. If still there are some doubts, feel free to comment back.

Let me summarize what we learned here -

1. We get shallow depth of field at high aperture (lower f value)

2. We get shallow depth of field, when distance between camera and subject is less.

3. If you don't want blurriness in your photograph, make sure that you are shooting from a distance and using lower aperture values (higher f value). E.g. - Landscapes

4. If you are not happy with blur you get at least f value, reduce the distance between your camera and subject. It will improve.