lenses

John Wiegley's BayHac 2017 talk walks through Haskell lenses by example, showing many practical uses beyond simple record access. It is aimed at people who want to become productive with the lens library.

Edward Kmett's talk to the NY Haskell User Group on the lens library, building from fmap and function composition up to lenses, folds and traversals. It shows how these composable combinators access and modify parts of data structures.

A through-the-lens comparison of the Oculus Quest 2, HP Reverb G2 and Valve Index, capturing what each headset's display actually looks like. It also previews a 90Hz mode coming to Quest 2.

Todd Becker's Ancestral Health Symposium talk arguing that myopia is driven by near-work and can be reversed, covering the biology and epidemiology and experimental evidence for reversal by using weaker lenses.

Huygens Optics explains the Fourier transform and shows how a lens performs one optically. A DLP projector is used as a Fourier filter to do simple pattern recognition on lithographic character patterns.

Applied Science shows how telecentric and hypercentric optics differ from normal lenses, producing no or negative perspective. The video builds a telecentric system from a Fresnel lens and demonstrates a lens that can see around objects.

Huygens Optics shows how DIY photon sieves shape a laser's wave front, explaining how they differ from zone plates and how aperture count affects the focal point, with time-resolved visualizations of the diffraction.

A video showing a virtual camera built in Blender that simulates lenses and film layers using path tracing, to make physically modeled photographs.