3/8-16 and 1/4-20 threads
The two screw sizes tripods use. 3/8-16 (3/8 inch, 16 threads per inch) holds heads on shooting tripods; 1/4-20 is the smaller camera thread, used for accessories and light gear.
What it means
Tripods and heads join with standard inch threads:
- 3/8-16: 3/8 inch across, 16 threads per inch. The standard for heads on shooting and full-size camera tripods. Most ball heads, leveling heads and saddles have a 3/8-16 socket underneath.
- 1/4-20: 1/4 inch across, 20 threads per inch. The camera thread. Small heads, phone and binocular adapters and many accessories use it.
Many tripod tops carry a reversible stud: 3/8-16 one way, 1/4-20 the other. Many legs also carry 1/4-20 or 3/8-16 sockets on the collars or the body for a light, a phone or a call.
What it changes in the field
A head with a 3/8-16 socket goes straight onto a 3/8 stud. A 1/4-20 head needs a bushing or the reversed stud. A heavy rifle head should sit on 3/8-16: the bigger thread holds better under recoil.
What to look for
- The stud size on the tripod and the socket size on the head you plan to use.
- A set screw or locking feature that stops the head unscrewing as you pan.
- Accessory sockets if you want to hang a light, call or phone off the legs.
How we use it on this site
Each tripod page lists the top’s mounting as the maker states it, plus any accessory threads the maker names.