That's a bit confused
Originally Posted by Bill Burk
There's a lug on the SMC Takumar lens that turns the meter on, however it does not de-activate the stop down metering switch which if used then gives false readings. So just trying it with a correct reading of a 30th @f5.6 when the stop down switch is used it claim itneeds a 30th @ f11 (both with SMC Takumar lens).
I had great difficulty persuading my wife not to use the meter switch on her K mount Pentax with its standard lens, this gave similar false readings.