So far, all my M42 adapters are simply tubes of proper length with M42 screwmount on one end and a Micro 4/3rds mount on the other. I open up and stop down the lenses via the M-A switch on my Takumars. I do have a few M42 lenses (Sigma for example) that do not provide a way to manually stop down the aperture. Does anyone know of any M42-m4/3rd adapters that are designed with either a switch to push the aperture pin in or do so when the lens is mounted? How about for K-mount lenses... Any PK adapters designed with a switch to open and close the aperture diaphragm for easier critical focus? side note: Today I went to a camera swap and was surprised to find a Minolta AF to m4/3rd adapter for $1 (somehow got included in a junk/rummage pile. The seller didn't know what it was). This particular adapter has a ring that rotates to engage the aperture lever in the lens mount. I'm hoping to find something simlar.