Tripod Threads
Tripod & Rigging · 6 specs
Direct Answer
ISO 1222 defines the standard mechanical screw threads used to mount photographic cameras, lighting accessories, and tripod heads. Standardizing on imperial UNC threads: 1/4"-20 UNC for camera baseplates and accessory cold shoes, and 3/8"-16 UNC for heavy tripod apex bases, fluid heads, and professional microphone boom poles.
Source: ISO 1222:2010 (Photography — Tripod connections) / ANSI/ASME B1.1 · Last reviewed Aug 28, 2026
Specs
| Standard Camera Base Thread | 1/4"-20 UNC (1/4 inch diameter, 20 threads per inch, 60° Unified Coarse thread) |
| Standard Tripod Head Base Thread | 3/8"-16 UNC (3/8 inch diameter, 16 threads per inch) |
| Camera Female Socket Depth | Minimum 5.5 mm to 6.5 mm thread depth in camera base |
| Male Screw Thread Length | Standard 4.5 mm to 5.0 mm threaded protrusion (prevents bottoming out against internal sensor chassis) |
| Reducer Bushing Adapter | Brass/steel 3/8"-16 to 1/4"-20 slotted reducer bushing (converts 3/8" sockets to 1/4" studs) |
| Domain Ubiquity | Universal across all DSLR/mirrorless camera bases, tripod quick-release plates, gimbal studs, monitor arms |
Why Cameras Still Use Imperial Threads
Even in fully metric countries (Japan, Germany), virtually all cameras use 1/4"-20 UNC and 3/8"-16 UNC threads. The lineage traces back to a 19th-century Royal Photographic Society recommendation for camera-mounting threads, though that original recommendation used the British Whitworth (BSW) thread form rather than today's Unified Coarse (UNC) form -- the two are close in nominal size but not interchangeable, and the modern UNC standard was only formalized later, arriving at today's specification via ISO 1222. An M6 metric screw will thread into a 1/4"-20 socket for half a turn before seizing and stripping the brass camera socket.