Please bear with me, sometimes I'm a bit slow.
I just loaded a friend's JPEG into ACR, to see if I could fix the distortion. The image has no EXIF. The list of Nikon-fit lenses was much shorter than usual - is this because it is a JPEG, rather than a raw file?
I was surprised that the 16-85mm lens wasn't in the list, as I know this was added in 6.2. After hunting for the LCP files, I see that there is a RAW version only, so this ties in with my guess. So, my next question is: why does Adobe supply two profiles with some lenses (raw + jpeg) and one with others?
I gave up on ACR, and loaded the JPEG into CS5. In CS5 Lens Corrections, I was allowed to assign a raw-only profile to my JPEG. This is good, but why am I allowed here, and not in ACR?
And, a less important question, but niggling nonetheless, and maybe a little off-topic, why does CS5 Lens Correction offer both "NIKON" and "NIKON CORPORATION" as a camera make, when others just have one listing?
Yammer P, yes the list is shorter because it's a jpeg rather than raw, and we have more profiles for raw than for jpeg.
For the set of lenses supported in CS5's initial release, we created profiles for both raw and jpeg. Since then, we have been concentrating on raw-based lens profiles, for a number of reasons (one of which is that we feel we can consistently deliver the highest quality results this way). This is why you see some lenses supported with raw & jpeg profiles, but many more supported with raw only.
CS5's Lens Correction plug-in does indeed let you choose raw-based lens profiles even though it is processing a rendered file (e.g., jpeg, tiff). This will work in many (but not all) cases for distortion correction, but will often work poorly for chromatic aberration and vignette correction. I don't recommend this workflow and it is a key reason we don't let users mix/match in ACR & LR.