In trying to figure out why my macro shots with my 40mm lens are so lackluster, I found a switch below the M/A M switch. It has FULL ∞-0.2m It does not make any difference which setting I use as far as trying macro's but what does it do? The first thing I did was go to the Nikon box to get the information that came with the lens but there was nothing in there but the velveteen pouch. I guess if it was in there I put it in a safe place..... Thanks