The Glossary

Every spec, defined in plain English

The terms and ratings that show up on packaging and in our reviews, translated out of marketing-speak. Bookmark it for the next time a spec sheet stops making sense.

CRI (Color Rendering Index): A 0–100 score of how faithfully a light shows color versus natural daylight. For lighting faces, aim for 95+ and ideally 97+; below 90, skin picks up an unhealthy cast that's hard to fix in editing.
Color temperature (Kelvin): How warm (orange, ~2700K) or cool (blue, ~5600K) a light appears. Matching your light's temperature to the room's dominant light keeps your face from clashing with the background.
IP rating (e.g. IP68 / IPX8): An Ingress Protection code. The first digit rates dust resistance (up to 6); the second rates water (7 = brief immersion to 1m, 8 = continuous immersion beyond 1m). 'X' means that property wasn't tested, not that it's zero.
Optical zoom: Magnification achieved by moving real glass, preserving full detail. This is the only zoom figure worth buying a camera for.
Digital zoom: Magnification achieved by cropping and enlarging the sensor's image, which softens detail. A '16X zoom' spec is often only a few multiples of optical zoom plus a long digital stretch.
SD Speed Class (C10): The original minimum sustained write-speed rating, shown as a number inside a C. Class 10 means at least 10MB/s — today essentially the floor.
UHS Speed Class (U1 / U3): A minimum sustained write rating shown inside a U. U1 = 10MB/s, U3 = 30MB/s. U3 is the practical baseline for recording 4K video without dropped frames.
Video Speed Class (V30 / V60 / V90): The newest sustained-write standard for video, shown as V plus a number equal to the guaranteed MB/s. V30 suits most 4K; V60 and V90 are for high-bitrate, 6K/8K, or high-frame-rate work.
UHS bus (UHS-I / UHS-II): The interface speed of an SD card, marked with roman numerals. UHS-II adds a second row of pins for higher peaks, but only reaches those speeds in a UHS-II device and reader.
Anti-reflective coating: A microscopically thin layer on lenses and glasses that reduces glare and reflections. It's delicate — dragging grit across it is what causes permanent hairline scratches.
Microfiber: A tightly woven synthetic cloth whose fine fibers lift oil and dust without fluid. Wash without fabric softener, which clogs the fibers and kills their grab.
MagSafe: Apple's magnetic mounting system on the back of newer iPhones. MagSafe selfie lights and accessories snap on instantly; thick cases weaken the hold unless you add a magnetic ring.
Buoyancy (floating pouch): A design feature that keeps a sealed phone pouch at the water's surface if dropped. Not automatic — check that a pouch is explicitly rated to float before trusting it on open water.
The tissue test: The habit of sealing a dry tissue in an empty waterproof pouch and submerging it for a minute before trusting your phone to it. Dry tissue confirms a good seal.