Years ago I had the 50mm f2.5 Macro, not life size (half, probably not an issue for timepieces perhaps) but tried and didn't like on a digital body, found it prone to colour drifts in the bokeh edges.
Now use a Sigma 70mm, albeit on a cropped body. However the lens is a DG type and so will work on full frame.
It's not a fast focuser, but has focus limiter, although you are probably using MF anyway.
VERY very sharp lens.
Worth a look if thats the kind of focal length you are looking at.
Reviewed very well, and I can vouch for it's performance, on APS-C at least.