My venerable Sigma 150mm f/2.8 EX DG IF HSM  macro (to use its full, slip off the tongue, title) virtually lives on a Nikon D7100 body.  For over a decade, it has seen heavy...

Maybe you have been attracted by the thought of the far lighter bodies of micro 4/3 cameras or the amazing array of functions (superb video and precision focusing aids for example) they boast...