Background Back in 2004 when I finally decided I needed to go digital, I was faced with the fact that my nice collection of Nikon lenses was "non-AI"-- that is pre-1977 lenses with the solid prong and which required the Nikon Twist (aka, shuffle, don't write) to "index" their maximum aperture for the TTL exposure systems on cameras like the Nikkormats and the F1 and F2. I wanted to know whether my lenses would work on Nikon digital SLRs or not. I wrote Nikon in the USA, no answer. I wrote Nikon in the UK, also no answer. I asked my friends who had newer Nikons. Wisely, as it turned out, they would not let me try my old lenses on their bodies. I looked all over the internet, and one of the few discussions I found on how to use non-AI lens Nikkors was Bob Atkins essay at http://www.bobatkins.com/photography/eosfaq/manual_focus_EOS.html on how to adapt them to Canon EOS cameras. Elsewhere, Bob also praised the Canon operating system as being natural for Macintosh users, as I recall. So to make a long story no longer, I ended up getting a Canon EOS camera and a bunch of cheap Nikon>EOS adapters for my Nikkors. Of course, I also started investing in Canon lenses to get AF and all the conveniences, but I was able to use my PC-Nikkor and other lenses without much more inconvenience than they were on my older Nikons. Also, there was stop-down TTL metering as well. However, if I could have got the information I am going to present below (and if the recent Nikon digital bodies had been available then), I might be a digital Nikon user today (I still shoot my old film Nikons regularly). Information on non-AI lenses and conversions First - here is a link to the Nikonians' compatibility table for Nikon and Nikon/Nikkor lenses: http://www.nikonians.org/nikon/slr-lens.html Here also is John White's site. As a 'preservationist' I am personally reluctant to modify old lenses. However, I know that there are otherwise well-meaning people who do not agree with this viewpoint. By all accounts (and he has been doing this for a long time I think back to 1977, in fact), White does a very nice job. If you need to covert, he is, I think, the place to go http://www.aiconversions.com/ However if I understand his website correctly, you can now safely mount non-AI lenses on the following: D40, D40X, D60, D3000, D3100, D5000 and D5100. If this is not so, respond here immediately, if you please, so a disclaimer can go in. Since some bodies can be damaged by non-AI lenses this is not just a curiosity issue. Always exercise care and you take your own responsibility for any lens cross-mounting you choose to do. White's table at http://www.aiconversions.com/compatibilitytable.htm gives details on the conversions and what is needed (BTW, also to put newer lenses on pre-AI bodies, but that's another story).