Notes, questions, and considered research. A little knowledge, collected along the way.https://starlight-code.comCompare how maximum aperture changes as you zoom, from the Sigma 20–200mm and Tamron 25–200mm G2 to longer and faster alternatives.https://starlight-code.com/posts/zoom-lens-aperture-comparison/https://starlight-code.com/posts/zoom-lens-aperture-comparison/Sun, 25 Oct 2026 00:00:00 GMTBuild a Sony full-frame lens kit around what you shoot, and decide what you give up when one lens serves several purposes.https://starlight-code.com/posts/choosing-a-lens-kit/https://starlight-code.com/posts/choosing-a-lens-kit/Sun, 25 Oct 2026 00:00:00 GMTExplore photos by lens.https://starlight-code.com/posts/focal-length-guide/https://starlight-code.com/posts/focal-length-guide/Sat, 24 Oct 2026 00:00:00 GMTExplore exposure, noise, motion blur and depth of field with a running dog, a hummingbird or a landscape focused at infinity.https://starlight-code.com/posts/exposure-triangle/https://starlight-code.com/posts/exposure-triangle/Sun, 18 Oct 2026 00:00:00 GMTSee an Airy disk on a Bayer sensor and calculate aperture from pixel size, sensor format and light color.https://starlight-code.com/posts/diffraction-calculator/https://starlight-code.com/posts/diffraction-calculator/Sun, 18 Oct 2026 00:00:00 GMTCompare the image circle required by five sensor formats with lens entrance-pupil diameters, and explore an animated 3D light path.https://starlight-code.com/posts/image-circle-and-aperture/https://starlight-code.com/posts/image-circle-and-aperture/Sun, 18 Oct 2026 00:00:00 GMTExplore how flickering light, shutter speed and sensor readout create bands in a photograph—and how panning tilts vertical lines.https://starlight-code.com/posts/banding-simulator/https://starlight-code.com/posts/banding-simulator/Sat, 17 Oct 2026 00:00:00 GMTFind a starting exposure with Sunny 16, or balance ISO, shutter speed and aperture for a chosen light level.https://starlight-code.com/posts/exposure-calculator/https://starlight-code.com/posts/exposure-calculator/Sat, 17 Oct 2026 00:00:00 GMTCompare up to four focal lengths on full frame and see how much of the scene each captures, from 6 mm to 1200 mm.https://starlight-code.com/posts/field-of-view-calculator/https://starlight-code.com/posts/field-of-view-calculator/Sat, 17 Oct 2026 00:00:00 GMTCompare four filter layouts, their surface areas, fan space and airflow directions with independent model presets.https://starlight-code.com/posts/air-purifier-filter-geometry/https://starlight-code.com/posts/air-purifier-filter-geometry/Sat, 17 Oct 2026 00:00:00 GMTCompare telephoto reach, teleconverters and Super 35 crops, and see how aperture relates to a chosen diffraction criterion.https://starlight-code.com/posts/sony-telephoto-lens-diffraction-calculator/https://starlight-code.com/posts/sony-telephoto-lens-diffraction-calculator/Sat, 17 Oct 2026 00:00:00 GMTEstimate the clean-air delivery your room needs from its volume and target air changes per hour.https://starlight-code.com/posts/air-purifier-sizing-for-haze/https://starlight-code.com/posts/air-purifier-sizing-for-haze/Sun, 11 Oct 2026 00:00:00 GMTCompare air purifier models by fan setting, clean air delivery, noise, and measurement source.https://starlight-code.com/posts/air-purifier-testing-standards/https://starlight-code.com/posts/air-purifier-testing-standards/Sun, 11 Oct 2026 00:00:00 GMT