I'm buying an enlarging lens on ebay, and from what I've read a 6 element lens is the way to go. However, where can I find the info. on the componon and el-nikkor lenses? Specifically, I've seen componon s, el-nikkor n, and other series listed here and on ebay. Are these lenses all 6 element? Does the N series in Nikon a better lens than just an "el-Nikkor" ? Thanks for any info!