Pentax 67 and SMC Pentax 67 165mm f/2.8 lens

Hello there,

I have an old Pentax 67 in my hands, with a SMC Pentax 67 165mm f/2.8 lens on it.

The lens has a AUTO / MANUAL switcher. Since it's a fully manual camera I guess I need to keep it in "manual", nevertheless I read somewhere that it needs to be in Automatic for the meter to work?

I'm confused.

Extra info:

- The meter needle moves in both settings

- The viewfinder becomes darker/lighter while changing the aperture only in the manual mode.

That switch is for the Depth of Field preview. Basically, keeping it in AUTO keeps the diaphragm fully open until the shutter is released. The meter will work with the switch in either position. When in auto, you will always see maximum amount of light through the viewfinder, but the meter will change when adjusting shutter speed or f/stop. When in MAN mode when looking through the viewfinder, the amount of light will change depending on what f/stop you are using. Hope that makes sense.

The AUTO mode is the default mode, to be used unless you put something between the lens and the camera body that disrupts the information flow from the lens (the helicoid tube for example). When this is done, the TTL meter has no idea of where the diaphragm is set, so you have to stop down the lens in MAN to the shooting aperture to get an accurate meter reading. There are 6x7 lenses that don't have this switch because they are manual diaphragm lenses; they are not AUTO lenses.