Shape of Bokeh


I have seen images that have beautiful round-shaped bokeh. I tried capturing such photographs but I seem to be getting only pentagonal-shaped ones in my pictures. Can you help me?
Ninad Parekh, Ahmedabad

It is the number of the diaphragm blades in a lens that determines the shape of a bokeh. For instance, a lens with five diaphragm blades will produce pentagonal bokeh instead of out-of-focus circles. The more the number of blades in the diaphragm, the more circular the bokeh will seem. To achieve round-shaped bokeh, check the number of diaphragm blades the lens has—7 or 9 is ideal. If your lens is incapable of this, you can alter the bokeh’s characteristics too! Use the widest aperture and in front of the lens, put a black paper that has a cutout of the required bokeh shape.

Tags: bokeh, diaphragm blades, Question of the Day, shapes, widest aperture