At least one of my film SLR cameras have the ability to 'lock-up' the
mirror once the shot is prepared for

Rob in Calgary

wrote:
wrote:
I've got a really basic question: Where does the image you get in the LCD
and EVF come from ?
Does it come from the sensor ?
Usually directly from the sensor.

If so, how does the shutter speed works, do they close the shutter, discharge
the sensor, and re-open the sensor for the appropriate time ?
There are no more shutters in many of today's digital camera.

That's not correct, unless you're writing about the absolute bottom of
the range digicam.
All digital cameras with an EVF and almost all with a LCD have a
shutter, it is just open while giving the live preview (the image
displayed on the EVF or LCD) and closes briefly to flush the sensor
before taking the exposure for a still image.
That is what gives the EVF/LCD type digicam a longer shutter lag, even
if they are set to manual focus and exposure modes.

With electronic viewfinders, the sensor is always on. When you push the
shutter button, it saves the image to storage (simplified version).

That may be correct for a movie mode on a digital stills camera, but
not for normal single exposures on most digicams available today.