The depth of field refers to the distance between the nearest and farthest objects in an image that is in acceptable focus. Shallow depth of field essentially means that the distance is between the nearest and farthest objects in focus is very small, thereby throwing the remaining foreground and/or background elements out of focus. This can be achieved by varying a variety of factors and is an interesting technique used by photographers to selectively focus on the subject to simplify an image, create pleasing effects in foreground/background as well as draw attention away from distracting elements in the background/foreground of a frame.
What is Bokeh?
The term “Bokeh” has a Japanese origin (boke) and means blur. In popular opinion, bokeh is associated with a blur of small specular highlights and light sources. However, in reality, bokeh refers to blur present in any out of focus areas of images that have a shallow depth of field.
Techniques of creating a bokeh effect in an image:
- Focusing Distance
To achieve good bokeh effect, the focusing distance, i.e., the distance between subject and camera should be minimum, to create a shallow depth of field
Larger aperture creates a shallower depth of field and therefore better bokeh
- Sensor size
Larger the sensor size, better the bokeh effect in an image. This is because to achieve the same image size with a larger sensor size, one would have to either use a longer focal length or move closer to the subject as compared to a smaller sensor size, thereby resulting in a shallower depth of field.
- Focal Length
Telephoto lenses create better bokeh than wide lenses. This is because a telephoto lens fills the frame with a much smaller area of background, thereby magnifying the size of a blur as compared to a wide lens.
- Distance: Subject to Background/ Foreground
Increasing the distance between the subject and background/ foreground creates or increases the bokeh effect in an image by increasing the distance of background/ foreground from the plane of focus.
Bokeh can be implemented in pictures in either background or foreground in a variety of shapes, such as creamy, round, polygonal as well as customized. Further, these can be used individually in an image or in combination, as can be observed in images that follow. In general, a bright spot, such as a light source, will blur out in a specific shape, depending upon the shape of the light source as well as the shape of lens opening (determined by lens aperture and the number of aperture blades in the lens). This is the cause for circular and/or polygonal bokeh that is frequently observed in images.
The following picture shows an example of creamy background bokeh and has been achieved using a large aperture (f/2.8).
In the above picture, a high aperture (f/4) coupled with a large subject to background distance has created a shallow depth of field, resulting in a creamy background. The lights in the background have blurred to form a circular shape. Thus, this image has a combination of creamy and circular background bokeh.
The above image shows how bokeh can have different shapes depending on the background. Thus, selecting an appropriate background can help us achieve the desired results in terms of any specific bokeh shapes that we might want. Also, as one would expect, the farther an element from the zone of focus, the blurrier it becomes in the resulting image. This can guide the placement of elements in a frame depending upon whether the bokeh is creamy or of a particular shape.
The above image is an example of a circular background and foreground bokeh. The background bokeh is achieved by selective placement of point light sources in the background, while the foreground bokeh is simply a refraction of the sources through the plastic surface on which the shoe has been placed.
The above image is an example of polygonal foreground bokeh. This has been achieved by placing a glass sheet with water drops in the foreground. By varying the distance of the glass sheet from the subject, and the lens aperture(f/4), the desired bokeh shape was achieved.
Often it is assumed that bokeh can only be achieved using a high aperture, but that’s not always true. With the correct choice of lens, focusing distance and subject to background distance, it is possible to achieve bokeh even at low apertures. Following are examples of images with beautiful bokeh shot at a low aperture.
The following image is an example of creamy background and foreground bokeh achieved at a low aperture (f/13) with an extremely small focusing distance (using a macro lens) to create an extremely shallow depth of field while maintaining distinct details in the subject.
The above image is yet another example of creamy and round bokeh at a low aperture (f/16).
The following image demonstrates circular background bokeh achieved at low aperture (f/18). An LED panel is kept behind the subject. The LEDs of the panel fall outside the depth of field of the image and have, hence, formed circularly shaped bokeh in the background.
The above image shows polygonal background bokeh at low aperture (f/16) achieved by maintaining a less focusing distance and a large subject to background distance. The background is formed by rays of a setting sun, filtered through leaves of a tree at a distance.
The following image is a variation of the previous image with a slight change in the composition to include a creamy foreground bokeh. Clearly, foreground blur is a lot less prominent than background because the foreground is much closer to the plane of focus as compared to the background.
Custom Bokeh Shapes
As already mentioned above, bright spots in a frame will blur out in a specific shape, depending on the shape of the lens opening. Thus, to achieve a custom shape bokeh, cut-outs of the custom shape (such as heart, star, etc.) can be placed in front of the lens to modify the shape of the lens opening, thereby causing the blur of light sources to be recorded in customized shapes.
As seen above, bokeh can be used as an extremely effective tool in creating aesthetically pleasing images. So do try out these tips and take your photography to the next level with some fascinating bokeh. Happy shooting!