Originally posted by robgo2 I use the LensAlign system for focus calibration and follow their guidelines exactly.
That should rule out user error.
Originally posted by robgo2 What are the alternatives to the DA*55/1.4, assuming that I am unsuccessful in obtaining one that works?
In that focal length range, I personally could recommend the K55/1.8 and the Nokton 58/1.4, both MF lenses but you probably want AF.
Originally posted by robgo2 The Sigma 50/1.4 HSM is highly regarded, but it is very large and heavy. It is also said to be closer to 45-47mm than to 50mm in true focal length, in which case, I would just as soon get the 43 Limited.
Is the Sigma really larger than the DA* 55/1.4?
Regarding focal length: Note that the stated focal length is for infinity focus only. If someone "measured" the Sigma for closer focusing distances, it is no wonder that the focal length was lower than 50. Same would hold true for the DA 55/1.4. Since DPRreview reckons the focal length might only by 47mm there might be some truth to it, though.
However, there is still quite a difference between 43mm and 47mm. Not trying to talk you out of the FA 43 which surely is a heck of a lens.
I regard the difference between 43 and 55 as very large. The 43 would not be as ideal for close portraits as the 55 is.
P.S.: Perhaps you can write to Pentax and ask them what's up with their QC. If you end up not buying the lens because you couldn't get a good copy, I'd definitely tell them about it. Constant dripping, wears the stone...