Originally posted by krBlues Perhaps DSLR cameras just 'get old' and need to be put out to pasture?
While manufacturers would love that, no it's not true.
1) Are you shooting from a tripod? If so then shake reduction should be off. If you are not using a tripod you might try that. I always use one for product shots. It just makes things easier.
2) What distance are you shooting from? There is a minimum focusing distance. I swapped lenses during a product shoot once and everything after the lens swap was blurry because the new lens had a longer minimum focus distance. It is quite possible to get an in focus beep but have the subject blurry because the camera focused on something in range but the subject is in the foreground and not in focus.
3) The 'in focus' beep is close but not really 100% accurate depending on the aperture you are using. Its a good guide but don't rely on it when working close in.
4) What aperture are you using? Too small and you will not get the entire object in focus
5) Try using Liveview on a tripod and see if that helps. Liveview uses a different focusing system.
6) It would really help to see some images with the EXIF intact. Otherwise we are just guessing and throwing out suggestions.
7) If you are using the viewfinder make sure the diopter is set properly.