Almost always one of four things, and in this order: no card or a full one, a lens not seated, focus not confirmed in single-shot mode, or a flash still charging. None of them is a fault.
A camera that will not fire is usually protecting you from a frame it cannot write or cannot focus.
The order worth checking
- Card. Missing, full, or locked by the small switch on its edge. Some bodies can be set to fire without a card and many refuse by default.
- Lens. Seated and turned to the stop. A partially mounted lens is a broken circuit.
- Focus. In single-shot mode the shutter waits for confirmation. A flat surface or a dark corner never gives it.
- Flash. A unit still recycling holds the shutter until it is ready — one product here publishes a recycle time of 0.01 to 2.5 s.
What is further down the list
A battery too flat to move the shutter while still showing a charge; a lens with a mechanical aperture unable to actuate on an adapter that passes no contacts.
What this is not
Not the shutter count, which is a wear figure rather than a lock. Not the card speed class, which affects writing rather than firing.
The thirty-second version
Card in and not full, lens clicked home, aim at an edge, wait for the beep. Three of the four are free to check and cover nearly every occurrence.
What people ask before they commit
Why does focus stop the shutter at all?
Because single-shot autofocus is designed to refuse rather than to deliver a frame it knows is out of focus. Aimed at a flat wall or a dark corner it never confirms, so the button does nothing — which looks like a dead camera and is a working one declining. Aim at an edge, or switch to manual.
What if the lens is mounted but nothing happens?
Take it off and put it back, watching that it turns to the stop and clicks. Contacts that are not seated present as a body that will not fire, and on adapted lenses the same applies twice — at the mount and at the adapter. An adapter that passes no contacts also means no aperture control, which is published per adapter rather than implied by the mounts.
Last reviewed 12 September 2026