I'm not sure a problem (if present) with aperture actuation would be in entirely in the lens. The body has the aperture coupling mechanism that is moving very fast. This moving mass could have an effect even if the lens is pre-stopped down. I've shot with OM-1 cameras for years but mostly hand held so I have little experience with tripod use. I have a notion that any problem with resolution at slow shutter speeds would be due to subject motion and not camera vibration.