Has anyone done this? I just bought the *istDL kit with the 18-55mm lens. I also have a manual focus Pentax 645 system with a bunch of lenses. Has anyone bought the adapter ring and tried this out? They vaguely say that it works but may have some restrictions with the functions. Does it run the aperture blades and still have ttl metering? I don't want to do this if it'll only run at full open aperture like a mirror lens. It's $150 for the adapter so it's a little bit of an investment so I wanted to find out if it'll work out before buying it. Thanks.