Originally posted by GeneV I have both the DFA 50 and 100, and I use them both equally. The 50 also has the advantage of being one of the sharpest lenses ever made for Pentax, if you care to use it for other subjects which require ultimate detail. The 100 is usually about the minimum for live bugs IMHO.
Agreed.. for an all around macro lens, I wouldn't go much shorter than 100mm
But, in this case, since you are only using the macro for musical instruments.. it is not a requirement..
That said, if you end up discovering that you want to take photos of bugs and stuff.. 100mm minimum is a good baseline. Actually, I have a 105mm Sigma macro and, at times, I wish it was longer.. bugs are skittish creatures and the more room you can get between them and your lens the better.