Standards
What a specification settles, and what it leaves open
Almost every figure on a camera or a lens comes from a document somebody else wrote: a mount and the flange distance behind it, a thread diameter, a shoe and its contacts, a measurement protocol. Those documents are exact, and they are exact about narrower things than a box implies. One page per standard, built in four parts — what the organization publishing it actually pins down, what it deliberately leaves open, what it expects to sit alongside, and which families here depend on it.
Lens mounts
The bayonets makers publish, the flange distance behind each one, and what an adapter can and cannot recover between two of them.
Filter threads
The diameter in millimeters printed beside the ⌀ symbol, the step rings that join two of them, and why the number is a property of the lens rather than the body.
Flash & sync
Hot shoe contacts, the sync speed a shutter publishes, and the difference between a guide number and an energy in watt-seconds.
Tripod threads & plates
The two screw sizes every support in this catalog uses, the plate profiles that clamp onto them, and which of those profiles is a published standard.
Sensor formats
The format names printed on a body, the dimensions behind each name, and the factor that turns an engraved focal length into an equivalent one.