Ordinarily, a point this out of focus would not be visible - its light would be too spread out over the film plane - so we have to make it artificially bright to show up ( RIB for example). The default aperture is circular we can see this by using a small, bright point that is out of focus. Some examples (note that Depth Of Field must be enabled for Bokeh effects): and 1 gives you a bright rim (bad bokeh). The default of 0 gives a constant brightness (neutral bokeh), -1 is brighter at the center and a falloff towards the edge (good bokeh). You are able to mimic the good (or bad) light falloff in your lens by using this control. Thus giving your highlights a more rounded shape.ĭensity: 'Good bokeh' is classed as having a brighter center and a falloff towards the edges in each de-focused point of light. Roundness: The roundness will curve the edges of our aperture blades in order to give them a more rounded appearance. Changing the number of sides causes our once perfect circular highlights to facet with as many sides as specified (three sides, for example, produces a triangle).Īngle: This spins the aperture around, rotating the out-of-focus points. Sides: The number of diaphragm blades does not technically control bokeh, but does control the shape of your blur circle (but not how light is distributed within it). The aperture shape is controlled by the aperture hider option: Hider 'raytrace' 'float aperture' You can specify the number of sides (i.e., blades) for the shape of the aperture, rotate the angle of the aperture, make the sides of the aperture bow inwards or outwards (i.e., change the aperture's roundness), and control the aperture's density to alter the shape of the brightness. RenderMan's virtual camera offers fine control over the aperture's shape and behavior. Some modern day cameras have curved edges on the aperture blades, or a greater number of blades to make the bokeh closely match a circle as much as possible. When the aperture is stopped down from its maximum size the out-of-focus points are blurred into the polygonal shape of the aperture, instead of perfect circles. Poorly corrected lenses will show one type of disc in front of the focal distance and another type behind, which may be desirable, as these circles with a dimmer edge can produce smoother less-defined shapes in the surrounding image. Depending on how the lens has been corrected for spherical aberration (imperfections caused by light rays striking a mirrors edge), the disc may be uniformly illuminated (“constant” bokeh), brighter at the edge (“bad” bokeh), or brighter near the middle (“good” bokeh). A point in an image that is out of focus is no longer rendered as a point, but a blurred disk.

It is related to the camera's aperture and quality of the lens. Bokeh, created by manipulating the apertureīokeh is a term used to describe the quality of blurring in out-of-focus areas of an image.

Camera bokeh shapes