Keyfeel refers to how a keyboard switch feels when pressed.
Keyfeel covers several distinct factors:
- Force curve: whether the switch is linear, tactile, progressive rate or some other type, and the shape of the force curve
- Weight: whether the switch requires a light or a heavy touch to operate
- Smoothness: how smooth or rough the key feels when operated
How smooth a key feels is determined by a combination of materials and mechanism. Keys that involve parts that rub together, as is frequently the case with metal contact switches, will inherently have a rougher feel due to metal parts dragging across plastic parts. Even metal-on-metal action is not free from friction. Non-contact keystroke sensing reduces the friction to a minimum, yielding a smoother switch.
The tactile mechanism itself involves changes in the shape of the parts (such as leaf spring flexing) and this itself can introduce jitter to the feel of the switch.
Loose switches vs full keyboards
The feel of a switch also depends on how it is being used. For reasons yet to be understood, some switches feel quite different when tested loose in comparison to how they they feel when typed on within a keyboard. The commonly-cited example is a lack of tactility. This characteristic applies especially to Mitsumi switches; for example, Mitsumi miniature mechanical yellow feels highly tactile when a loose switch is pressed, but by most accounts it is far less tactile during typing. The Mitsumi version of the Apple Extended Keyboard II was considered to be essentially linear, and from machine translations of MouseFan's and Sandy's accounts of the switch it uses (a alternative variant of Type 2 Mitsumi standard mechanical), it appeared to be considered a linear switch that was weakly tactile. Testing with a loose switch suggests that it should be very tactile, but in reality this seems not to be the case.
No explanation for these differences has yet been found; for now, testing of loose switches must come with the caveat that typing on such switches may yield a very different outcome.