December 8, 2022
You can achieve lots of Subtle Realism by using custom aperture maps!
Bokeh is an element ever-present in life. Whether you look through a camera lens with crafted optics, or through your own eyes.
There is always bokeh.
I’ve been working on a cgi bokeh tutorial and experimented a lot with aperture maps :)
In my long process of R&D to improve my rendering this was one area I’d often overlooked.
I first wanted to solve a personal challenge. How to match our eyes’ bokeh?
The above aperture map and test is my first attempt at Eye bokeh. I made this texture in Photoshop by combining a large variety of eye-surgery photographs.
Extracting the right color values was a bit tricky but I’m quite happy with how it turned out.
When I defocus my vision I see a pretty similar bokeh shape. I feel like there should still be a bit more contrast.
I’m excited to work on this more and then animate it into an image sequence :)
Alright, here are some tests with a Heptagonal over-compensated aperture:
In the above examples you can see the subtle effects of the bokeh, even on a Wide Depth of Field like F/16.
On F/1.2 the effects become extremely obvious. The heptagonal aperture geometrically splits the focal chart triangles.
Both of these examples are with low chromatic aberration. I will soon be rendering some more tests with higher levels of aberrations, as well as different aperture imperfections.
For those with lens-experience you probably know about the following:
Lenses (both organic and crafted) come in a variety of shapes. But the light distribution within that shape can vary lots from lens to lens.
A 13-sided aperture can be under-compensated (light collects in the center, giving soft edges), balanced (slightly sharp outlines, evenly lit blur disk) or over-compensated (light collects to the sides, creating halo bokeh).
Bokeh implies the feel of your out-of-focus areas. For this reason it’s important consider your choice of aperture map when making a render :)
Once I’m done developing more aperture maps I’ll share a product for it!
Including an After Effects and Photoshop file to quickly build your own maps!
The Look-Dev setup I’m using is also available on my store, including a Free Download UV Checkerboard texture!
Thanks a lot for reading!
Have a great day! Cheers, Leo