Additional Photography Information:
Photography Basics – The Bokeh Effect
Have you noticed certain out of focus circles in images? Do you appreciate portrait images with blurred (out of focus) background? Does it not highlight the portrait against the overall scene? But, do you feel that it must not happen, as camera should capture what your eye is seeing. Do you see it as a defect?
It is not at all a defect; in fact, it has got lot of artistic value. We call it “The Bokeh effect”. These are basically “out of focus” parts of the image. Bokeh is most artistic, when we have light sources in the scene. It creates blurred out circles of light sources, giving a distinct effect, not visible to a normal eye.
To create bokeh effect of light sources, you need some object in foreground and multiple light sources (small enough to be capture in one frame) in the background. For e.g., in the image of Christmas lights below, we need focus on any light series in the front, rest of the light sources will create the bokeh effect.
We will discuss the technical details behind it and also learn how to create bokeh effects in simple ways. (It is anyway a very simple to create it).
It depends on the four factors:
The Aperture: Larger the Aperture better is the bokeh effect. In fact, Aperture plays most important role in creating bokehs. For good bokeh, we need apertures larger than F/2.8. Larger aperture throws the background out of focus, which creates this effect. The shapes of these circles are same as that of diaphragm. We can even create the shapes of our choice, using as external filter with required shapes.
The focal length: Larger the focal length better is the bokeh effect. We need to shoot at the longest focal length of the lens to create good bokeh effect. However, we can play with different focal lengths here. If you recall, most of the wildlife and sports images have background blurred. This is primarily because; these images have been taken at very long focal lengths (more than 300mm).
The distance from the subject: Closer the distance from the subject, the better is the bokeh effect. For a good bokeh effect you need the main subject as close as possible (which you want to keep in focus). This is why, in Macro shots (which are taken from close distance), it gets difficult to keep everything in focus. However, we never face such problem in shooting landscapes, where most of the objects are at fairly large distance.
The image below is taken from a very short distance from the earthen pots. The background light sources have created the bokeh. You can see the pentagon shapes, which is actually the shape of the diaphragm blades of the lens.
The sensor of the camera: Larger the sensor better is the bokeh effect. We do not get a good bokeh effect in point and shoot cameras primarily because of the small sensor size. For good bokeh, a D-SLR camera with larger aperture is an important ingredient. But, even if you do not have a D-SLR, you can combine the other three factors to create bokeh.
In the image below, a Garden Lizard has been captured from a close distance, at a large aperture and at a longer focal length using a D-SLR Camera.