Nine rounded iris blades guarantee images with a harmonic bokeh
You probably come across this sentence quite a lot when reading about new lenses. But what are the technical characteristics behind this phrase? And what has this got to do with the iris?
Indeed, this topic has been discussed several times and some of you might think that this is unexciting topic. But we are convinced that you will not be bored reading this article. We will show an unusual way of how you can understand depth of field using very little geometry.
Don’t worry – Aside from some simple exceptions we will not be talking about mathematical formulas at all. Our goal is to understand the interactions and introduce to you some hands-on rules of thumb. Knowledgeable facts and figures can be found in some tables and illustrations. After all this, it will only be a small step to fully understand what hides behind the mysterious term ‘bokeh’. While the geometric theory of depth of field looks at the topics from an idealized point of view you have to take the real characteristics of each lens into consideration. This means that you have to respect the minor flaws of each lens in order to understand the meaning of ‘bokeh’. The iris itself is simply not enough – This much can be said in advance.
Read the full article here.