Leica, Aperture & f/stop info

Question

As many of you know, and has been well documented on this discussion board:  When impporting Leica DNG files into Aperture: the f/stop and detailed lens info is not displayed by Aperture.
A work around which adds one step:  Initially import the photos into either Adobe Photoshop or Adobe Lightroom-- do nothing to them and then export them as DNG files...effectively nothing has changed.  Then import them directly into Aperture:

Answer 1

I think I understand the questions being asked here, but please forgive me if not. Certainly I can talk about the M9.
With the Leica M system of cameras there is no mechanical or electronic connection between the lens and the body that transfers information about the lens' aperture setting. That is, the camera does not know what the lens is set to and so does not have metadata for aperture, f-stop, whatever. As such, there is no f-stop metadata for software like Aperture to work with.
The thing to be aware of is that the Leica rangefinder camera concept dates from the 1920s, revamped into the current system in the 1950s, with digital capability added in the 2000s. Think of an M9 as a box with a very nice sensor to which a long history of very nice lenses can be attached and you've got it. The latest lenses can tell the M9 camera what they are (via a physical code engraved on the lens' bayonet mount which is read by the camera) but cannot transfer f-stop metadata. There is none to transfer and no means to transfer it if there was. They are purely mechanical lenses that make superb images.
M9 images do include metadata for parameters other than f-stop, as the camera body does know what shutter speed was used, what the ISO was, etc.