When looking for Nikon info, the Mir site is probably the best hands down. It has a ton of information along with clear images that covers pretty much everything.
I have the 24mm and 28mm f2 ais lenses and both have the crc which focuses down to 1 ft. I think the easiest way is to look at the lens barrel and if you see the marking for 1ft then it is most likely crc. I have never shot with the 20mm, it is pricey and I think it doesnt pop up as much (the mf version, there are lots of the plastic af version). I had the 35mm 1.4 ais and it also had the crc.
here is a link to the site to get you started:
Last edited by Newt_on_Swings; 05-24-2013 at 02:58 AM. Click to view previous post history.