Depth of Field

Optical Vignetting

Optical vignetting can be used to simulate vignetting created by lens hoods and matte boxes.

The default circular shape will create the familiar Cat's Eye effect that can be found in many lenses.

The barn doors of camera matte boxes, used to prevent lens flares, can also create mechanical vignetting, which can be recreated in Photographer.

While this may not be intended by the camera operators, this effect can be seen in many movies such as Taxi Driver, Michael Clayton, La La Land...

It is possible to be creative and use other shapes such as a tilted rectangle.

Bokeh Texture (Cycles and LuxCore only)

Every lens has its own way of rendering out-of-focus. This is due to the number of glass elements, their quality of transmission, their cleanliness, the numbers and shapes of aperture blades, etc…

From these imperfections comme different type of bokeh rendition:

  • Flat (what is usually considered good quality)

  • Outer Ring, common with low quality older lenses, often creates a busy out-of-focus

  • Onion rings, common with zoom lenses

  • STF (Smooth Trans Focus), made to give a creamy and soft out-of-focus.

  • Mirror lenses (or Reflex lenses), uses for long telephoto primes.

  • Dusty, which could creates black spots in the middle of the bokeh

On top of that, the aperture blades can affect the shape of the bokeh, from circular to hexagonal, octogonal, etc… While you could do that with the Blender Blade setting, you will notice that the result screams CGI because it give perfect straight lines to the blades.

In real lenses, lenses with a low blade count (5 - 8) often have curved blades. And blades also often create little notches at the corners. These imperfections could be done with a Bokeh texture.

For some very specific effects, one can give any shape to the bokeh using a black paper cutout.

Note that Bokeh texture can be colored, and this is handy to recreate some sort of longitudinal chromatic aberration.

You may have noticed that out-of-focus areas are other greenish after the focus area, and purple-ish in front of the focus area.

While this would require a complex diffraction setup that would take a long time to render with Cycles, you could decide to tint the edge of your bokeh shape in green to get a similar effect.
I recommend green because it is often stronger and more noticeable than purple, as you often have more background out-of-focus than foreground out-of-focus.

Credits: opticallimits.com

Example of visible front and back focus longitudinal chromatic aberration.

Consider that rendering bokeh textures can require an insane amount of samples in order to refine all details of the texture.
I’d recommend to keep the textures rather simple, or to exaggerate details such as dusts to really see them appear.
You also need the emissive object creating the bokeh to be very small so it starts creating a perfect bokeh.

A lot of interesting information about lenses and bokeh can be found on this website: http://richardrosenman.com/shop/dof-pro/

Photographer 4 Live Demo video also contains a lot of information about how to use Optical Vignetting and Bokeh textures.