You might ask yourself what this is and why it is in the gallery, but bear with me:
The images you see are Luxcore renders done with bidir caustics. The photographic chart you see is only a caustic effect, the plane itself is white diffuse with no texture.
Before I go into details: Watch the video below - it shows the whole process and will make everything much clearer.
after the video - here are some more details:
This is a ‘real’ photographic lens, more specifically a so called ‘cooke-triplet’ that I built from scratch - so no reference values were used beyond copying the rough layout of the three lenses.
The first part of the process happens in Rhino / Grasshopper where I built a parametric lens template and a whole evaluation system for light rays (in 2d).
Running the parameters through a genetic optimization algorithm (Galapagos) it found a ‘good’ solution - meaning a lens configuration that produces a sharp image at a given distance.
After that I exported the lenses as objs to blender and gave them a glass shader, build a housing, film plate and placed a emitter with a texture (the chart) in front of it at the right distance.
Additionally, here is a big screenshot from the Grasshopper setup. I would wish that Grasshopper gets a bit more attention in the discussion on everything nodes. Because it is being worked on for about 10 years and it does many things very well (conceptually)
Full setup (aperture and lens body are hidden)
caustic result with small aperture:
caustic result with large aperture: