Even if you’ve never heard the word bokeh before, you’ve certainly seen it in action hundreds of times, and most likely have attempted to utilize it in your own videos. Bokeh is a japanese word that translates to blur. In practice, bokeh refers to the way the blur looks in an image. The most distinct example being bright points of light.
Each lens has different characteristics that literally shape the way the out of focus areas in your shot look. Bokeh is formed from the optics of the lens that is design to the shape of the aperture opening. When more blades are used in an iris design, the resulting bokeh appears more circular, while lenses with fewer blades appear with multi-sided shapes.
Of course, which of these is more pleasing, is completely subjective. However, there are some characteristics which are generally agreed on.The blurred areas of a shot should be smooth, even, and soft, without color shifts or ghosting.
Lets take this canon 50mm prime as an example, to test its bokeh, it would seem to reason that shooting fully open at f/1.2 Would be the best way to judge the bokeh of that lens. Because there is so much blur associated with shooting wide open, it becomes problematic when judging the shape of the bokeh. Instead, shooting a bit smaller aperture, say f/4 to f/5.6 Will allow the blur to not inhibit the judgment of the bokeh.
Overall, bokeh is something to consider when buying a lens. Because it’s subjective, figure out what type of bokeh is of your taste. Once your favor is known, research why that bokeh looks the way it does, and choose your lens accordingly.
