Lens question

I think that Einstein have covered the answer quite extensively but I just want to extend on his answer, if you are looking for an adapter from MD to MA, Minolta made an adapter named M/A converter, these adapters are 2x convertors at the same time, this is one which is available now from ebay

http://www.ebay.co.uk/itm/GENUINE-MINOLTA-SONY-2X-M-A-CONVERTER-S-WORLD-SHIP-JAPAN-/321053970296?pt=LH_DefaultDomain_0&hash=item4ac04ecf78

otherwise if you are using the lens only for macro then you should buy an adapter without a lens but you will lose infinity focus.