Light Gathering Index (Photon Flux): Light gathering capability is proportional to the physical entrance pupil area: Area × (1 / N²) where N is the focal ratio (f-stop). A 1-inch sensor at f/1.6 captures 2.8× more photons per millisecond than a 1/1.56" sensor at f/1.9.

Equivalent Depth of Field (DoF): Full-frame 35mm equivalent aperture is computed as f_equiv = f_physical × Crop Factor. While mobile phones advertise "f/1.4" or "f/1.6", the optical crop factor (3.2× to 3.8×) yields depth of field equivalent to f/4.5 - f/6.0 on a mirrorless camera.

Pixel Binning (Quad / Nonacell / Hexadeca): A 200MP sensor with 0.56µm pixels bins 16 adjacent photosites into a 2.24µm equivalent super-pixel at 12.5MP, lowering read noise and improving signal-to-noise ratio in low lux scenes.

Periscope Folded Optics: Periscope lenses redirect light 90° through a prism down the chassis, enabling 120mm+ focal lengths without physical lens protrusion.