Optical Blur
& Depth of Field

Blurriness has always fascinated me. An infinite source of aesthetic creation, it is an integral element of cinematic storytelling. Over the years I have spent studying and producing images myself, I have always questioned the origin of this blur and the means of modification available to us as cinematographers.

In this thesis, I aim to analyze the direct and indirect factors that influence optical blur and explore the methods we have at our disposal to anticipate and measure the formation of this blur. Blur is a tool in the creative process, and its usage can be delicate. It is crucial to understand its origin in order to effectively employ it in service of storytelling.

We will first examine the formation of blur within our cinematic image, along with the important elements that result from it, depth of field, hyperfocal distance, circle of confusion. We will then explore the tools we have to analyze and quantify optical blur in order to anticipate its formation on our photosensitive surface. Finally, we will delve into a range of common cinematographic elements that allow us to finely modulate this optical blur.

Our investigation will be supported by diagrams to enhance understanding of the formation of depth and blur, images from tests or films used to illustrate the blurry experiments of encountered cinematographers, as well as images from my practical research to present my approach to optical blur.

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PDF, Master's thesis · Max Decamps · ENS Louis Lumière