The Aperture ring on the pre-AI lenses is too wide and will break the metering index tab on DSLR's. The modification removes material from the aperture ring of the lens so that the metering tab will work correctly. John White in Ann Arbor, MI does the conversions for $35.00 each for a Type "B" conversion which is what you want to use the lens on your D80. Here is a link to his website: http://www.aiconversions.com/index.html He has a lot of information regarding compatibility and FAQ. Good Luck and Enjoy your Nikons!