Francesco, nice to see you having some fun with watch and camera. For some time now I have admired the use of HDR mainly in landscape work but never ventured down that road nor applied it to my watch photography. In its basic form it can be rather harsh but with experience and toying around with different software the results can be pleasing. The very few attempts I made with watch pictures were so bad I never went back. I prefer to use layers and the example below is a case in point. Its a technique known as focus stacking and has some similarities with HDR in the way the images, each focused at different point from front to back, are combined. Once again you can get software to do the stacking for you i.e. it selects the sharpest focus points from each image and combines them together (similar to the HDR best exposure technique). The tool in Photoshop CS5 wasn’t that good either so I did it manually with layers and layer masks. This image is a combination of 8 different images each one set at the same exposure and aperture but focused at different point from to back. That is why it is sharp from front to back. No other way of achieving this with a DSLR (may be possible with a plate camera). It’s a well used technique in watch advertising but with my limited software it was a pain to do so its my only example.

Keep experimenting and I look forward to more examples.
regards
Paul