I have a bunch of Nikkormats and some more modern Nikon backs (FE, EL2, FG, etc). I have been trying to look into lenses to use with them that are AI compatible (so I can use them on both the older and the newer backs). I am most interested in "off brand" lenses that are less expensive but still very good. I have read some excellent reviews of the Kiron lenses. Can anyone recommend any other off brand lenses that are considered very high quality? Especially zooms?