Originally posted by reh321 If I understand correctly, "green button" metering uses the aperture control mechanism, so that would stress the system some.
If I understand more recent comments correctly, "green button" metering will not work once this problem occurs regularly. As nearly as I can tell, the only reliable "work around" is a lens that stays stopped down the entire time. That can be a pain, because opening up the lens gives more light for framing and more sensitivity for manual focusing {these being why it opens up in the first place}, but the camera is definitely useable this way. As far as I can tell, that leaves three options, all using lenses with an aperture ring
(1) some here have cut off the aperture lever {I hate the thought of crippling a lens that way - but if its your lens...}
(2) using an M42-mount or other lens which has an "auto/manual" switch, which will allow you to keep it stopped down all the time
(3) I found a way to modify my AdaptAll lenses to keep them stopped down all the time
Keeping AdaptAll Lens Stopped Down - PentaxForums.com