,"The
light meter is constantly switched on but there is an automatic cut-off when the light is at
EV2 or less, so it is important to keep the lens cap on when the camera is not in use, in order to conserve the battery."
I don't think this is correct. I tried out my father's Spotmatic this afternoon (because mine doesn't have a battery in it). The manual says that to test the battery, put the shutter speed to B and ASA to 100 and turn on the meter. The needle should move down if the battery is o.k.
I did this and noticed that the initial movement of the switch closed down the aperture (it's not an F) then after a bit more movement, the meter needle moved so there is definitely a switch there.
I have heard about keeping the lens cap on some Pentax cameras such as the K1000 and the KM as they don't have meter switches but this thread is the first time I have heard it referred to for a Spotmatic. It also seems silly to me that someone would design a camera with a switch/lever which you had to move to meter, call it a meter switch in the manual but not actually have a switch there.
Someone here must have taken one apart and could give us a definitive answer.
If the information in the Camerapedia link is correct then I think it must only apply to the F model.
Steve.