Originally posted by jatrax AFAIK the lens ID is in the "Maker Notes" section of the jpeg, which is not standard and the software has to be updated to understand how the maker has stored the info. The DNG however is standard so it makes sense that the software can read the lens codes from there.
No k-30 here so I can't help with testing but it sounds as if the k-30 jpeg EXIF has a change from others. At least you know the camera is not malfunctioning.
You should be able to see the maker notes section in Exiftool and you might be able to see what has changed if you have an older jpeg. You can also add the correct lens ID from within ExifTool. I do this (when I have time) for my Takumars. You have to put the name you want in the LensModel field rather than in the Maker Notes section but it works.
When I say, shows no lens Exif data, I mean it just doesn't show which lens I used. f stop, focal length, shutter speed, etc is all there, just not which actual lens I had on the camera.