I just ordered a Panasonic 45-150/4-5.6 lens in advance of a trip we have coming up. I note that it seems to have had several releases indicated by model suffixes. It's officially the H-FS45150* (where the * is either S or K, for silver or black). When I went to order it I noticed that some vendors list the model number as H-FS45150A*, and others list it with E*, and the box I have has an adhesive label with the model number given as H-FS45150PKA (and that label covers the model number printed on the box, but doesn't prevent me from reading that it said H-FS45150E-K). By my count that's at least four revisions (original, A, E, and P*A). Anybody know what changed in those revisions? Mine's got serial number XA5KD00nnnn if that's useful info for comparison. I know some old reviews complained of variations between different copies of the lens, so are all these revisions just indications of process changes, or do they suggest quality control improvements? Note: I'm not looking for a reason to send it back or anything. So far it checks out with acceptable sharpness for what I need, and the Olympus 40-150/2.8 Pro is too big/heavy/awkward for the situation I'll be wanting to use a long lens. I'm just curious.