A chronograph mechanism that uses a cam and lever system, rather than a column wheel, to control the start, stop, and reset functions. Generally more affordable to produce, though considered less refined.
Cam-actuated chronographs, sometimes called lever chronographs, control their start, stop, and reset functions using a shaped cam that pushes against a series of levers, rather than the rotating, stepped column wheel used in higher-end chronograph movements. It's a simpler mechanism with fewer, less intricately finished parts, which makes it cheaper and generally more robust to manufacture at scale.
The trade-off shows up mostly in the feel of the pushers: column wheel chronographs are typically prized for a lighter, more precise actuation, while cam-actuated versions tend to feel slightly stiffer. Plenty of well-regarded movements use cam-actuation, though, and the distinction matters more to enthusiasts than it affects everyday reliability.
Not in terms of reliability, cam-actuated mechanisms are typically robust and cost-effective. The main difference enthusiasts notice is pusher feel: column wheel chronographs are generally considered to have a lighter, more precise actuation.
It uses fewer, simpler parts, making it cheaper to manufacture and often more robust, which is why it's common in chronographs at more accessible price points.
Not from the outside. The difference is internal, in how the pushers connect to and control the chronograph's start, stop, and reset functions.