Recently a friend saw this (and some other) pictures and asked about how I was getting the perfect DOF for such images, and specifically asked about what I do in the field rather than what is published in the books and the articles.
okay so for technical details and the bookish stuff on DOF (depth of field) refer to this wikipedia article. For what my personal “trick” is… read on 🙂
DOF as we know is the sharp area behind and in front of the subject aht we see in pictures. A shallow depth of field (very less foreground and background in focus) makes the subject stand out, as it has in the squirrel picture above. Typically, a shallow DOF is used for portraits, birds, animals and any subject which you want to isolate from its surroundings. A wide DOF is typically used for landscapes where you want everything from the foreground to the background to be sharp.
The one thing that makes for beautifully blurred background is how close you are to the subject. If you’re very close to the subject (which is the case with the picture above), you will be able to greatly distance the background from the subject. The moment this happens, you automatically get a very shallow DOF. The thumb rule here is… the closer you are to the subject, the shallower the DOF, and the further you are… the deeper the DOF. DOF is relative to your distance from the subject.
If you notice macro shots, for example a flower, to get the full flower sharp, you will typically need an aperture value of f/16 to f/22. If you try the same flower at f/5.6 or f/8, you’ll get only a small part of the flower sharp while the edges will be blurred. So try this thumbrule in the field… try getting close to the subject and then click at f/5.6 or f/8 and you will get some dramitc DOF results 🙂
In addition, another thumb rule that I apply is, a longer lens (telephotos and super telephotos) will have a shallow DOF, while wide lenses and macro lenses have much wider DOF.
Keep a few of these in mind, and experiment with your subject distances to get the right DOF for your captures. The following examples illustrate the DOF and distance concept.
The 4 pictures below have been clicked at f/4 using a focal length of 105mm. The distance between the two objects has not been changed for any of the shots. I moved forward and backward to click these pictures.
Also notice the sharpness of the object in the foreground (the one which has focus)